PROJECT PLAN FOR

IMPLEMENTING NAD 83 IN THE

MINERALS MANAGEMENT SERVICE

PART II: Technical Aspects of Implementation

(INTERNET VERSION)

Prepared By:

Paul Rogers, Cartographer

Mapping & Survey Staff Boundary Branch

For:

Leland F. Thormahlen, Chief

Mapping & Survey Staff Boundary Branch

Denver, Colorado

May 3, 1993
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PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

OUTLINE/TABLE OF CONTENTS

page

 i. Preface to Internet Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

NARN/HPGN Status as of 1/7/99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

 ii. Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

 1. INTRODUCTION ................................................. 1

 2. OFFICE OF MANAGEMENT AND BUDGET (OMB) CIRCULAR A-16 ........ 1

 2.1. Federal Geographic Data Committee (FGDC) ........................ 5

 2.2. Interior Geographic Data Committee (IGDC) ......................... 6

 3. NAD 83 CADASTRE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

 3.1. NAD 83 (1986) and High Accuracy Reference Network (HARN)

 (NAD 83 (199x)) Coordinates ..................................... 8

 3.1.1. HARN Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

 3.1.2. NAD 83 (1986)/NAD 83 (199x) Positional Differences .............. 9

 3.1.3. Adjoining State HARN Coordinate Compatibility .................. 9

 3.1.4. HARN Impact on the MMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

 3.1.5. MMS HARN Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

 3.1.6. Mapping & Survey Staff (MSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

 3.1.7. Offshore Systems Center (OSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

 3.1.8. OPDC Supervisory Program Analyst . . . . . . . . . . . . . . . . . . . . . . . . . . 11

 3.2. Official Protraction Diagrams (OPD's) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

 3.2.1. Replacement of Leasing Maps (LM's) . . . . . . . . . . . . . . . . . . . . . . . . . 12

 3.2.2. Block/Boundary Coordinates and Areal Measurements . . . . . . . . . . . 12

 3.2.3. International Maritime Boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

 3.2.4. Provisional Maritime Boundary Note . . . . . . . . . . . . . . . . . . . . . . . . . . 13

 3.2.5. Exclusive Economic Zone (EEZ) Limit Boundary . . . . . . . . . . . . . . . . . 13

 3.3. Supplemental Official OCS Block Diagram(s) (SOBD) . . . . . . . . . . . . . . . . 14

 3.4. Supplemental Official Composite Block Diagram(s) (SOCBD) . . . . . . . . . . 14

 3.4.1. OCS Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

 3.4.2. Office of International Activities and Marine

 Minerals (INTERMAR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

 3.4.3. Mapping & Survey Staff (MSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

 3.5. Supplemental Official Lease Diagram(s) (SOLD) . . . . . . . . . . . . . . . . . . . . 15

 3.5.1. OCS Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

 3.5.2. Office of International Activities and Marine

 Minerals (INTERMAR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

 3.5.3. Offshore Systems Center (OSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

 3.5.4. Mapping & Survey Staff (MSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

 3.6. Plot Unit Diagrams (PLUD's) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
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 3.6.1. OCS Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

 3.6.2. Office of International Activities and Marine

 Minerals (INTERMAR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

 3.6.3. Mapping & Survey Staff (MSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

 3.7. Summary of MMS NAD 83 Cadastre-related Products . . . . . . . . . . . . . . . . 17

 3.7.1. Standard Computational Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

 3.7.2. Specialized Computational Products . . . . . . . . . . . . . . . . . . . . . . . . . . 17

 3.8. Historical Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 4. DATUM TRANSFORMATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 4.1. Transformation Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 4.1.1. OCS Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

 4.1.2. Mapping & Survey Staff (MSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

 4.1.3. Offshore Systems Center (OSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

 4.1.4. OPDC Supervisory Program Analyst . . . . . . . . . . . . . . . . . . . . . . . . . . 20

 4.2. NAD 83 Coordinate Equivalent Values for Non-NAD 83

 International Maritime Boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

 4.3. Leasehold and Boundary Integrity When Transforming . . . . . . . . . . . . . . . . 20

 4.3.1. Case 1: Blocks leased under NAD 27 . . . . . . . . . . . . . . . . . . . . . . . . . 21

 4.3.2. Case 2: Ambulatory boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

 4.3.3. Case 3: U.S. Supreme Court Decreed Boundaries . . . . . . . . . . . . . . . 22

 4.3.4. Case 4: International Maritime Boundaries . . . . . . . . . . . . . . . . . . . . . 24

 4.3.5. Case 5: Subdividing Irregular Portions to

 Create Bidding Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 4.3.6. Form MMS-2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 4.4. Orphan Datum Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

 4.4.1. Orphan Datum Transformation Procedure 1: To Obtain

 NAD 27 Coordinates From Orphan Datum Coordinates . . . . . . . . . . . . . 26

 4.4.2. Orphan Datum Transformation Procedure 2: To Obtain

 NAD 83 Coordinates From Actual NAD 27 Coordinates . . . . . . . . . . . . . 27

 5. MMS/GEOLOGICAL SURVEY (USGS) AGREEMENT . . . . . . . . . . . . . . . . . . . 27

 5.1. MMS/MSS Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

 5.2. USGS Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

 5.3. MMS/USGS Joint Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

 6. DEPARTMENT OF STATE (DOS) COORDINATION . . . . . . . . . . . . . . . . . . . . 29

 7. ST. MATTHEW ISLAND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

 8. COMPUTATION OF PROJECTED MARITIME BOUNDARIES BEYOND 

 12 NAUTICAL MILES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

 9. APPENDIX A--NAD 83 OPD FORMAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

 9.1. NAD 27 OPD/LM Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

 9.2. NAD 83 OPD Format Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
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 9.3. Industry NAD 83 OPD Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . 38

 9.4. NAD 83 OPD Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

 9.4.1. Block Number Numbering Scheme Rationale . . . . . . . . . . . . . . . . . . . . 39

 10. APPENDIX B--NON-MATHEMATICALLY DEFINABLE CURVES RESULTING

 FROM DATUM TRANSFORMATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

 10.1. Conversion of SPCS Coordinates to Geodetic Coordinates,

 South Pass Area, South Addition, LA Map 9A, Block 78,

 Lambert Projection, Louisiana South Zone . . . . . . . . . . . . . . . . . . . . . . . . . . 43

 10.2. NAD 27 to NAD 83 Latitude and Longitude Transformations

 Using NADCON Version 2.00, South Pass Area, South 

 Addition, LA Map 9A, Block 78 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

 11. APPENDIX C--North American Datum Conversion NAD 83 (1986) to

 NAD 83 (199x) Using Selected OCS Preliminary Baseline 

 Points for the States of Florida, Oregon, and Washington in

 NADCON V2.10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

 12. APPENDIX D--ACRONYMS & ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . 47

FIGURES

Figure 1. MMS NAD 83 planning area conversion schedule as determined

by the MMS NAD 83 Implementation Team . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Figure 2. Structure of the Federal Geographic Data Committee (FGDC) .......... 2

Figure 3. Structure of the Interior Geographic Data Committee (IGDC) ........... 3

Figure 4. Assumed NAD 27 leaseholds in the Gulf of Mexico OCS Region 

(from a portion of Leasing Maps LA-Map Nos. 8, 9, and 9A) 

depicted on the NAD 83 cadastre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 5. Standard NADCON V2.00 directory configuration for the

MMS Alaska OCS Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 6. Cadastre 1: Typical numbering scheme for Leasing Maps

referencing the Louisiana SPCS--LA Map No. 10 (Main 

Pass Area) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 7. Cadastre 2: Typical numbering scheme for Leasing Maps

referencing the Texas SPCS--(portion) TEX Map No.1 (South 

Padre Island Area) and TEX Map No. 1A (South Padre Island 

Area, East Addition) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
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Figure 8. Cadastre 3: Typical numbering scheme for Leasing Maps

referencing the California SPCS--(portion) CAL Map No. 6E 

(Channel Islands Area) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figure 9. Cadastres 4 and 5: Typical numbering scheme for

NAD 27 Official Protraction Diagrams 44 cadastre grid

blocks wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 10. Cadastre 5: Typical numbering scheme for NAD 27

Official Protraction Diagrams 47 cadastre grid blocks

wide in the Alaska OCS Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 11. NAD 83 OPD numbering scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
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i PREFACE TO INTERNET VERSION

This January 8, 1999, Internet version of “PROJECT PLAN FOR IMPLEMENTING

NAD 83 IN THE MINERALS MANAGEMENT SERVICE, PART I: Responsibilities

and Timeframes,” is identical to the official May 3, 1993 version released by the

Minerals Management Service except as noted below:

 The original document was developed using a Helvetica type style in

WordPerfect version 5 and a Hewlett Packard LaserJet Series 2 printer. This

Internet version was reformatted using an Arial type style in WordPerfect

version 8, and a Hewlett Packard LaserJet 4MV printer. This has resulted in

page numbering being slightly different from the original document.

 The name and phone number of the office within the Minerals Management

Service responsible of developing and maintaining the offshore cadastres has

been revised on the cover page.

 Figure 1 was redrawn using WordPerfect 8.

 Figures 2 and 3 were redrawn using Corel Presentations 8.

 Figure 4 was scanned in TIFF format from the original manually drafted figure.

 Figures 5 - 11 remain in the original document format, although the type style

and point size of the figures has been change.

 A definition has been added on page 32.

 A HARN/HPGN status graphic drawn using Corel Presentations 8 has been

added on the following page.

 NAD 83 has been implemented in the Alaska, Atlantic, and Pacific OCS

Regions. The Gulf of Mexico OCS Region continues on NAD 27.
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PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

ii. EXECUTIVE SUMMARY

Over the last five years (1987-92), the Minerals Management Service (MMS) has

evaluated and tested various options for implementing the latest United States (U.S.)

horizontal control datum--the North American Datum of 1983 (NAD 83). Initially the

MMS examined not only what impact NAD 83 would have on the Agency, but also

should the conversion be made from the North American Datum of 1927 (NAD 27) to

NAD 83. In June 1989, the Federal Government officially adopted NAD 83 (54 FR

25318, June 14, 1989), rendering moot any option the Agency may have had in not

converting. All efforts were then directed towards how to convert to NAD 83 with

minimal adverse program impact and expense.

There are two major aspects to MMS implementation of NAD 83. First, the Agency has

to implement NAD 83 with minimal program disruption, while maintaining the integrity of

existing NAD 27 leaseholds. MMS's phased approach to NAD 83 implementation

based upon the "Comprehensive Program" (Figure 1), specialized transformation

procedures, and the parallel implementation of the Technical Information Management

System (TIMS) accommodate this requirement.

OCS Region/*

Planning Area

Sale**

Number

Sale** Date MMS Target

Completion

Date***

OCS Region/*

Planning Area

Sale**

Number

Sale** Date MMS Target

Completion

Date***

Alaska/

 Beaufort Sea

 Chukchi Sea

 Cook Inlet/

 Shelikof Strait

 GOA (Yakutat)

 Hope Basin

 St. George

144

148

149

158

159

153

12/95

6/96

9/94

8/95

7/97

12/96

2/95

2/94

10/93

12/94

9/95

3/95

Atlantic/

 Mid-Atlantic

 South Atlantic

Gulf of Mexico/

 Eastern GOM

Pacific/

 Southern CA

 Wash./Oregon

164

164

151

N/A

N/A

10/96

10/96

10/95

N/A

N/A

11/94

11/94

TBD

TBD

TBD

*Conversion schedule for planning areas not listed to be determined at a later date by the MMS NAD 83 Implementation Team.

**”Comprehensive Program 1992-1997,” April 1992.

 N/A = Not Applicable.

***Completed OPD’s and SOBD’s due to regional office.

 MSS = Mapping & Survey Staff.

 TBD = To Be Determined.

Figure 1. MMS NAD 83 planning area conversion schedule as determined by the MMS NAD 83

Implementation Team.

That is not to say that every conceivable issue or problem has been addressed in the

project plan. At every level of government and private industry, NAD 83 implementation

is a dynamic process as the advent of the High Accuracy Reference Networks (HARN's)

illustrates.

HARN's are NAD 83 refinements, initiated by, and within, select individual States. 

However, technology, such as used in the Persian Gulf War, and the mushrooming use

of Land and Geographic Information Systems (LIS/GIS), created a demand for more

accurate positioning/surveying capabilities in the civilian sector than the original NAD 83
 1

 The year in parenthesis after NAD 83 indicates the year of adjustment, with the main NAD 83 adjustment

occurring in 1986. HARN adjustments will be dated sometime during the 1990's, with 199x indicating the year of

adjustment is unknown at this time.

 2

 Relative positioning is the location of features by relating their position in relation to known positions--e.g., well

locations so many feet or meters south/north and east/west of block boundaries.

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adjustment (NAD 83 (1986)) provided. In response to this need, the National Geodetic

Survey plans to develop HARN's for all States over the next five years, effectively

creating a second NAD 83-based horizontal control network (NAD 83 (199x)1.

Second, MMS employees must become datum conscious and verify datum references. 

Prior to 54 FR 25318 most Agency employees did not have to relate coordinates to a

specific datum. MMS coordinate and associated data referenced NAD 27, and although

other datums existed, MMS did not develop data tied to them. However, the United

States adoption of NAD 83 directly or indirectly affects every aspect of the Agency's

mission. Since the adoption of NAD 83, every locational coordinate (e.g., shot points)

and areal measurement (e.g., the number of 8(g) hectares on a Supplemental Official

OCS Block Diagram (SOBD)) must carry a specific datum reference. Do they reference

NAD 27? Do they reference the original NAD 83 adjustment--NAD 83 (1986)? Do they

reference a HARN--NAD 83 (199x)? Assumptions are no longer acceptable; the

mixing of datum-referenced data can cause major problems and expense for the

Agency.

The MMS holds and develops data which appear to be non-datum dependent. Some of

this data, however, has a direct relationship to coordinate data which are datum

dependent. For example:

! Rental fees and royalties for blocks leased within a planning area are

derived from areal measurements computed from cadastre grid and

boundary coordinates which are datum-dependent.

! Recent relative positioning2

 well spots have probably been

developed from cadastre grid and boundary coordinates, especially if

Global Positioning System (GPS) surveying, navigation, and

positioning techniques have been employed to spot wells.

This two part document amplifies the MMS NAD 83 Implementation Plan outlined in the

56 FR 20020, May 1, 1991. The first part, "Project Plan for Implementing NAD 83 in the

Minerals Management Service, Part I: Responsibilities and Timeframes," details the

various aspects of implementation, organizational unit responsibilities, and estimated

timeframes. The second part, "Project Plan for Implementing NAD 83 in the Minerals

Management Service, Part II: Technical Aspects of Implementation," details specific

technical aspects of the MMS conversion from NAD 27 to NAD 83 and identifies

associated organizational unit responsibilities. 
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PART II –Technical Aspects of Implementation

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PROJECT PLAN FOR

IMPLEMENTING NAD 83 IN THE

MINERALS MANAGEMENT SERVICE

PART II

Technical Aspects of Implementation

1. INTRODUCTION

If switching from NAD 27 to NAD 83 were as easy as converting English measurements

to metric or converting latitude and longitude to state plane coordinates, the conversion

process for Minerals Management Service (MMS) would be relatively simple. Unfortunately, an exact transformation between NAD 27 and NAD 83 does not exist. They

differ systematically because of a change in the reference ellipsoid and randomly

because of errors in computations, known distortions in NAD 27, and the inclusion of

many new observations in the calculation of NAD 83. Also, almost all of the new

observations were made with newer, more accurate instruments.

There are two aspects to the MMS implementation of NAD 83. First is the creation of a

cadastre based on NAD 83. Second, most of MMS's existing data and boundaries must

be transformed from NAD 27 to NAD 83.

This two part document amplifies the MMS North American Datum of 1983 (NAD 83)

Implementation Plan outlined in Federal Register (FR) Notice 56 FR 20020, May 1,

1991. The first part, "Project Plan for Implementing NAD 83 in the Minerals

Management Service, Part I: Responsibilities and Timeframes," details the various

aspects of implementation, organizational unit responsibilities, and estimated

timeframes. The second part, "Project Plan for Implementing NAD 83 in the Minerals

Management Service, Part II: Technical Aspects of Implementation," details specific

technical aspects of the MMS converting from NAD 27 to NAD 83 and identifies

associated organizational unit responsibilities.

The documents can be used independently. However, they are intended to be used in

association with each other. Each document is cross-referenced to the companion

document.

2. OFFICE OF MANAGEMENT AND BUDGET (OMB) CIRCULAR A-16

"Coordination of Surveying, Mapping, and Related

Spacial Data Activities"

On October 19, 1990, the Office of Management and Budget (OMB) issued the revised

OMB Circular A-16, titled "Coordination of Surveying, Mapping, and Related Spacial

Data Activities." The revised Circular expands the breadth of coordination of spatial
 3

 Spatial data are geographically referenced features that are described by geographic positions and attributes in

an analog and/or computer readable (digital) form.

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Figure 2. Structure of the Federal Geographic Data Committee (FGDC). The Steering

Committee provides policy guidance and oversight to the activities of the Subcommittees and

Working Groups. Subcommittees coordinate activities related to each spatial data category. 

Working Groups deal with issues common to all spatial data categories and promote consistency

among the activities of the Subcommittees.

data3 and assigns leadership roles to Federal Departments for coordinating activities

related to these data. The revised Circular also establishes a new interagency

committee called the Federal Geographic Data Committee (FGDC). (See Figure 2.) 

The objective of the FGDC is to promote the coordinated development, use, sharing,

and dissemination of surveying, mapping, and related spatial data activities. Therefore,

data policies developed by this committee will directly affect the Agency's

implementation of NAD 83.

The Circular assigns to the Department of the Interior the responsibility of chairing the

Committee. In order to provide effective government-wide leadership to this expanded

spatial geographic data coordination process, the Department must update and

enhance its internal spatial data coordinating mechanisms.

In addition, a new intradepartmental coordinating committee, called the Interior

Geographic Data Committee (IGDC), was created with the primary objective to promote

the coordinated development, use, sharing, and dissemination of surveying, mapping,

and related spatial data within the Department of the Interior. (See Figure 3.) In

addition, the IGDC will: 
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Figure 3. Structure of the Interior Geographic Data

Committee (IGDC). The Steering Committee provides policy

guidance and oversight to the activities of the Regional

Subcommittees and Working Groups.

! Advise and assist the Secretary of the Interior in developing and implementing

policies and strategies to reduce duplication in spatial geographic data

development, and to promote technology transfer and data exchange.

! Provide a focal point on Interior surveying, mapping, and related spatial data

activities with the FGDC, and other Federal entities.

! Coordinate bureau viewpoints on surveying, mapping, and related spatial data

issues.

! Coordinate the planning of spatial data technologies research (e.g.,

geographic information systems and remote sensing) within the Department of

the Interior. 

The committee will establish, in consultation with other appropriate Department

organizations, such standards, procedures, interagency agreements, and other

mechanisms as are necessary to carry out its department-wide coordinating

responsibilities. Like the FGDC, the data policies developed by this committee will

directly affect the Agency's implementation of NAD 83.

The Geological Survey has been assigned the responsibility of organizing, chairing, and

providing staff support to the IGDC. The Geological Survey is also the chair of the

FGDC, and this dual responsibility will ensure a strong linkage between Interior and
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government-wide coordinating mechanisms for spatial data activities. The other

members will include senior representatives from the Bureaus of Indian Affairs, Land

Management, Mines, and Reclamation; the Fish and Wildlife Service; the MMS; the

National Park Service; the Office of Surface Mining; and the departmental Offices of

Information Resources Management and Program Analysis. Other senior officials will

be invited to attend meetings of the IGDC as appropriate in light of the issues to be

discussed. In addition, each bureau and office that has activities related to the

development, use, sharing, and dissemination of surveying, mapping, and related

spatial data should actively support and participate in the activities of the IGDC.

Subcommittees and working groups may be convened to support specific needs as

identified by the IGDC. Initially, six working groups (Surveying, Mapping, Resource

Applications, Standards, Geographic Information Systems, and Remote Sensing) and

two regional subcommittees are recommended to carry out the IGDC's department-wide

coordination responsibility. (See Figure 3.)

The IGDC will prepare and publish an annual report to the Secretary. This report will

describe the activities conducted by, and accomplishments of, the committee during the

fiscal year, including appropriate spatial data activities of the bureaus.

There are for MMS purposes three important documents developed as a direct result of

the Revised OMB Circular A-16, they are in chronological order:

! The Secretary of the Interior's Memorandum, dated February 1, 1991,

establishing responsibilities for bureaus in the Department of the Interior to

execute the government-wide leadership roles assigned by the Circular.

! The Chairman, Offshore Information Management Committee's Memorandum,

dated April 30, 1991, to the Associate Director Offshore Minerals Management

describing the importance of participating in the FGDC and IGDC processes.

! The Associate Director for Offshore Minerals Management's Memorandum,

dated May 21, 1991, to the Executive Secretary, FGDC naming

representatives to committees and subcommittees and deferring

representation to the various working groups until learning more about their

specific functions, objectives, and needs.

Since that time, the MMS has become more active in the various FGDC and IGDC

committees, subcommittees, and working groups. To date the MMS is represented on

the following FGDC and IGDC committees, subcommittees, and working groups:
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2.1. Federal Geographic Data Committee (FGDC)

A. Subcommittees

1. With MMS Representation:

a. Base Cartographic .............. Lee Thormahlen

b. Cadastral .................... Lee Thormahlen

c. Geodetic Control . . . . . . . . . . . . . . . Alice Drew

d. Geologic . . . . . . . . . . . . . . . . . . . . Michael Hunt

e. Bathymetric . . . . . . . . . . . . . . . . . . . Lee Thormahlen

2. Without MMS Representation:

a. Ground Transportation

b. Soils

c. Vegetation

d. Wetlands

B. Working Groups:

1. With MMS Representation:

a. Under the FGDC Subcommittee on Cadastral data, the

 MMS is represented on two working groups.

1) Offshore Cadastral Working Group

.............. Lee Thormahlen

2) Land Records Working Group

. . . . . . . . . . . . . . Paul Rogers

b. Under the FGDC Subcommittee on Geodetic Control, the MMS

 is represented on one working group.

1) High Accuracy Reference Networks (HARN's)

. . . . . . . . . . . . . . Alice Drew

2. Without MMS Representation:

a. Information has been requested to determine if additional

 working groups exist.

C. Technical Advisory Groups (TAG's):

1. With MMS Representation:
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a. Under the FGDC Subcommittee on Cadastral Data the

 MMS is represented on one TAG.

1) Development of spatial data standards for cadastral

 data . . . . . . . . . . . . . . . . . . . . Lee Thormahlen/Richard Naito

2.2. Interior Geographic Data Committee (IGDC)

Tom Readinger, Program Director, Office of Program Development and Coordination is

the MMS IGDC representative.

A. Subcommittees

1. With MMS Representation:

a. Steering Committee . . . . . . . . . . . . . Dave Bornholdt

b. Denver Regional Subcommittee . . . Lee Thormahlen

2. Mapping/GIS Implementation Plan Working Groups

a. Clearinghouse . . . . . . . . . . . . . . Yvonne Morehouse

b. Telecommunications . . . . . . . . . . . . Wally Macnow

c. Policy . . . . . . . . . . . . . . . . . . . . . . . . Dave Bornholdt

d. Base Cartographic .............. Lee Thormahlen

3. Without MMS Representation:

a. Western Regional Subcommittee

B. Working Groups

1. With MMS Representation:

a. Geographic Information Systems . . Jake Lehman

b. Remote Sensing . . . . . . . . . . . . . . Alice Drew

2. Without MMS Representation:

The IGDC Standards working group has been abolished, this function will be

accomplished by the FGDC. Therefore, MMS is currently represented on all

existing IGDC working groups. However,in mid-November 1992, a memorandum

from the Chairman, IGDC requested bureaus to designate their representatives

for four (4) new working groups. 

On October 28, 1992, Yvonne Morehouse was appointed to coordinate an effort to
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develop Offshore Cadastral Data Standards for the IGDC Mapping/GIS Implementation

Plan. Tentatively these standards will be completed in DRAFT form by March 1993,

and a DOI Manual Section will be prepared by April 30, 1993.

It is important that the readers of this paper make every effort to ensure that their

respective areas of responsibility are represented in both the FGDC and IGDC

processes. Currently both committees and their respective subcommittees and working

groups are actively developing standards that will affect and regulate the development,

use, sharing, and dissemination of surveying, mapping, and related spatial data

activities within the Federal Government. Many of the ongoing efforts will ultimately

lead to the development of Federal Information Processing Standards

(FIPS) and will affect future budget processes related to surveying, mapping, and

spatial data activities.

For more information regarding the FGDC you can request the following document from

Mr. Michael (Mike) Domaratz, Executive Secretary, FGDC at (703) 648-4533:

A National Geographic Information Resource

The Spatial Foundation of the Information-Based Society

First Annual Report to the Director,

Office of Management and Budget

by the Federal Geographic Data Committee

December 1991
 4

 A reference ellipsoid is a geometric approximation of the earth with specified dimensions and is associated with a

geodetic reference system or a geodetic datum. GRS 80 is the reference ellipsoid recommended by the International

Association of Geodesists as the reference ellipsoid best defining the shape of the earth for NAD 83. It was adopted

by the International Union of Geodesy and Geophysics in 1979.

 5

 See Part I, sections 2.2. and 8. for a description and history of the NAD 27 cadastres.

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3. NAD 83 CADASTRE

The MMS will have a uniform NAD 83-based cadastre throughout the Outer Continental

Shelf (OCS). The NAD 83 cadastre offshore of the continental U.S. will strictly adhere

to the definitive parameters of the Universal Transverse Mercator (UTM) Grid system,

using the Geodetic Reference System of 1980 (GRS 80) as the reference ellipsoid4

. 

The NAD 83 cadastre will not supersede the NAD 27 cadastres5. When a planning area

is converted to NAD 83, maintenance of the NAD 27 cadastre(s) for the planning area

will cease, except for error corrections. That is, when a geographic area is converted to

NAD 83, a new cadastre based on NAD 83 will be created. Thereafter, the new

cadastre will be maintained as required. The old NAD 27 cadastre, which will still be

required for certain purposes, i.e., maintenance of existing leaseholds, will be frozen in

place and no longer maintained except for correcting computational or typographical

errors:

! NAD 27 Official Protraction Diagrams (OPD's) and Leasing Maps (LM's) in

effect in a planning area on the date of its conversion to NAD 83 will remain in

effect perpetually. OPD's will not be revised unless they are found to contain

an error which will adversely affect NAD 83 projected boundary and/or areal

measurement computations.

! NAD 27 Supplemental Official OCS Block Diagrams (SOBD's) in effect in a

planning area on the date of its conversion to NAD 83 will remain in effect

perpetually. SOBD's will not be revised unless they are found to contain an

error which will adversely affect NAD 83 projected boundary and/or areal

measurement computations.

The Mapping & Survey Staff (MSS) will depict the NAD 83 cadastre on two standard

computational products--OPD's and SOBD's. Upon OCS regional or Office of

International Activities and Marine Minerals (INTERMAR) request, the MSS will depict

the NAD 83 cadastre on two specialized computational products--Supplemental Official

Composite Block Diagrams (SOCBD's) and Supplemental Official Lease Diagrams

(SOLD's).

3.1. NAD 83 (1986) and High Accuracy Reference Network (HARN) (NAD 83 (199x))

Coordinates
 6

 See footnote 1, page v.

 7

 Although HARN's were initiated by individual States, the NGS plans HARN coverage of the entire U.S. using a

100 kilometer grid (control station) interval. If a State opts to enter into a cooperate agreement with the NGS, a

denser HARN may be established.

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The offshore cadastre described above is compatible with either NAD 83 (1986)6 or the

emerging State- or region-specific High Accuracy Reference Networks7 (HARN's). 

However, unlike the datum change from NAD 27 to NAD 83 (1986), HARN (NAD 83

(199x)) coordinates are NAD 83 refinements.

3.1.1. HARN Status. As of October 1992, the National Geodetic Survey (NGS) status of

coastal States (and/or coastal region) HARN's was:

! HARN's established for Florida, Maryland/Delaware, and

Washington/Oregon.

! Computational adjustments in progress for Alabama, Alaska, California, and

Louisiana.

! Field operations completed in FY 92 for Maine, Massachusetts, New

Hampshire, New Jersey, New York, and Rhode Island.

! Field operations scheduled in FY 93 for Mississippi, Texas, and Virginia.

! Field operations highly probable in FY 94 for Georgia, North Carolina, and

South Carolina.

! HARN's probable, but field operations not likely until at least FY 95, for

Hawaii, Puerto Rico, and the Virgin Islands.

3.1.2. NAD 83 (1986)/NAD 83 (199x) Positional Differences. The NGS has predicted

NAD 83 (1986) and NAD 83 (199x) coordinates for most positions in the conterminous

U.S. to differ by less than one meter. However, portions of coastal Oregon exceed this

difference. (See Part II, Appendix C.) Most differences in Alaska were predicted to be

less than two meters; however, NGS has found differences of up to six meters. 

Over large areas coordinate transformations between NAD 27 and NAD 83 exhibit

nonlinear differences. The same is true for transformed NAD 83 (1986) and NAD 83

(199x) coordinates, albeit the differences are much reduced.

3.1.3. Adjoining State HARN Coordinate Compatibility. Although HARN's are being

developed on a State by State (or regional) basis, the NGS has indicated that their field

procedures and computational adjustments should ensure direct coordinate

compatibility with an adjoining state. For example, HARN coordinates for California

should be directly compatible with HARN coordinates for Oregon.
 8

 This version of NADCON recognizes the recently computed grids for the state and regional High Precision GPS

Networks (HPGN's), now known as HARN's.

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3.1.4. HARN Impact on the MMS. The MMS is affected by HARN's primarily along a

coastal State's land/water interface, i.e., the baseline. A baseline point's NAD 83 (1986)

and NAD 83 (199x) coordinates are on the same datum. Both sets of coordinates

correctly describe a point's NAD 83 location. Thus, boundaries projected seaward from

the baseline, using either set of NAD 83 coordinates, can produce correctly projected

NAD 83 boundaries. For example, either NAD 83 (1986) or NAD 83 (1991) coordinates

can be used to project Oregon's NAD 83 State Seaward Boundary (SSB) from the

baseline. Although the baseline points would be physically identical, their NAD 83

positional coordinate accuracy creates two different baselines and two different SSB

projections. Both of these projected boundaries would correctly intersect the MMS NAD

83 offshore cadastre, but with coordinate differences that could approach 1.5 meters. 

(See Part II, Appendix C for NAD 83 (1986) and NAD 83 (1991) Oregon baseline

transformation test results.)

3.1.5. MMS HARN Policy. First, since positional coordinates based on the 1986

adjustment and a HARN adjustment are both on NAD 83, the year of adjustment needs

to be cited/identified for all NAD 83 coordinates developed or received by the MMS. 

For example, Oregon NAD 83 coordinates referencing the 1986 adjustment should be

cited as: NAD 83 (1986); Oregon HARN referenced coordinates should be cited as:

NAD 83 (1991).

Second, the MMS will use NAD 83 (1986) coordinates for all baseline, projected

boundary, and other computations portrayed on the NAD 83 cadastre within each OCS

region. HARN coordinates (NAD 83 (199x)) will not be used. However, once the NGS

has established HARN's for all of the coastal States within an OCS region, this policy

will be reconsidered. After the MSS has tested and evaluated HARN coordinates, a

recommendation for a formalized policy will be made to the MMS Offshore Information

Management Committee (OIMC). The OIMC will issue formal MMS policy statements

related to HARN's.

Third, NADCON v2.108 (or later) will be used to transform between NAD 83 (1986) and

HARN (NAD 83 (199x)) coordinates. Until HARN coordinate compatibility has been fully

tested (probably not until at least late FY 93 or early FY 94) any coordinate

transformations between NAD 83 (1986) and NAD 83 (199x) should identify the

appropriate NADCON HARN grid(s) used to develop the coordinates (e.g., FL (or

Florida) or WO (or Washington/Oregon)).

Fourth, the MMS is an active member of the FGDC, Federal Geodetic Control

Subcommittee's (FGCS's) HARN Working Group. (See Part II, section 3.1.6.)

3.1.6. Mapping & Survey Staff (MSS). The FGDC, FGCS HARN Working Group will

study and review the impact of HARN's on the Federal Government. On completion of

the study, the Working Group will publish a report of its findings. The MSS Geodesist
 9

 When this document was written, OB2MIS was being converted to the Block and Boundary component of the

MMS Technical Information Management System (TIMS). Throughout the remainder of this document, both OB2MIS

and the Block and Boundary component of TIMS will be referred to as "B&B, TIMS."

 10 For MMS purposes WGS 84 is considered equal to NAD 83 offshore of Alaska and the conterminous U.S.

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will represent the MMS on this Working Group. The MSS Geodesist will be responsible

for recommending an Agency policy on HARN's upon completion of the Working

Group's report.

3.1.7. Offshore Systems Center (OSC). As appropriate, the Offshore Systems Center

(OSC) will revise the MMS Offshore Block, Boundary, and MAP/OPD Information

System (OB2MIS)9 to ensure compatibility with evolving MMS HARN policy. 

3.1.8. OPDC Supervisory Program Analyst. The Supervisory Program Analyst in the

Office of Program Development and Coordination (OPDC) will be the MMS NAD 83

Implementation Team liaison to the OIMC to develop MMS HARN policy. The OPDC

Supervisory Program Analyst will ensure compatibility with FGDC policy, and as

appropriate, publish the MMS HARN policy in the Federal Register.

3.2. Official Protraction Diagram(s) (OPD)

OPD's are the standard computational products which all other cadastre-related

products supplement. NAD 83 OPD's will depict a metric grid, with full grid blocks being

4800-by-4800 meters throughout the OCS. Areal measurements for partial blocks

along UTM zone boundaries will be shown on the OPD.

A standardized block numbering scheme will be based on the formula:

[(Row Number - 1) x 50] + Column Number + 6000 = Block Number.

For example, the OPD block number for the block in row 23, column 27 is 7127

([(23 - 1) x 50] + 27 + 6000). The OPD block number for the block in row 1,

column 12 is 6012 ([(1 - 1) x 50] + 12 + 6000).

The number of blocks per OPD will vary, based upon an OPD's latitude and location

within a UTM zone. (See Part II, Appendix A., section 9.4.)

When required, OPD's for Hawaii and the U.S. Dependencies will also portray a metric

cadastre based upon strict adherence to the definitive parameters of the UTM grid

system. However, due to the physical separation of some of these areas from the

continental U.S., the World Geodetic System of 1984 (WGS 84)10 may be substituted as

the reference ellipsoid in lieu of GRS 80.
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The first planning areas scheduled for conversion to NAD 83 are the Chukchi Sea and

Cook Inlet. (See Part I, Appendix B.) Construction of these OPD's will establish one of

two uniform, standardized MMS-wide NAD 83 OPD formats. (See Part II, Appendix A,

section 9.4.)

3.2.1. Replacement of Leasing Maps (LM's). All LM's offshore of Louisiana, Texas, and

a portion of southern California referencing NAD 27 State Plane Coordinate Systems

(SPCS's) will be replaced by OPD's. The English systems of measurement (feet and

acres) will be replaced by the metric UTM grid system (meters and hectares). These

changes will correct distortions and errors associated with some NAD 27 cadastres.

3.2.2. Block/Boundary Coordinates and Areal Measurements. B&B, TIMS will be used

to develop and maintain metric offshore block and boundary coordinates and areal

measurements. UTM "X" and "Y" block corners and boundary intersections will be

computed to three (3) significant decimal digits. Areal measurements will be computed

in hectares to six (6) significant decimal digits. This level of significant digits will facilitate

the numerous coordinate conversions and datum transformations between the various

NAD 27 cadastres and NAD 83. It will also facilitate the integration of, and consistency

between, existing and proposed information systems.

3.2.3. International Maritime Boundaries. NAD 83 OPD's will depict the Federal

Government's position relative to international maritime boundaries. The MSS will

determine the most appropriate portrayal of a boundary in consultation with the

Department of State (DOS): 

! For international maritime boundaries referencing NAD 83 or WGS 84,

coordinates for initial, turning, end, and other points will be described on

OPD's as specified in the treaty, agreement, or World Court decision

establishing the boundary. A datum reference citation as part of the point

description is redundant and will not be included. For example, the Initial

Point on the U.S.-U.S.S.R. Provisional Maritime Boundary, would be

depicted on NAD 83 OPD NQ 02-06 as:

I.P. 65E30'00"N 168E58'37"W.

! For international maritime boundaries referencing datums other than NAD

83 or WGS 84, coordinates for initial, turning, end, and other points will be

described on OPD's as specified in the treaty, agreement, or World Court

decision establishing the boundary. A datum reference citation will be

included as part of the point description. For example, Turning Point 12 on

the U.S.-Canada Maritime Boundary, would be depicted on NAD 83 OPD

NL 19-12 as:

T.P. 12 (44E49'43.625"N 66E57'57.134"W NAD 27).

! Generally, transformed coordinate equivalents for international maritime
 11 NADCON v2.00 (or later) is the standard MMS NAD 27/83 datum transformation software.

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boundaries will not be depicted on NAD 83 OPD's. If, however, it is

determined to be in the best interest of the Federal Government to cite

transformed coordinate equivalents, coordinates for initial, turning, end, and

other points as specified in the treaty, agreement, or World Court decision

establishing the boundary will be transformed using the current NADCON

version11. The word "Transformed" will be included as part of the point

description and the following note included on the OPD collar:

The National Geodetic Survey (NGS) software NADCON [version number] is

used by MMS to transform between NAD 27 and NAD 83 coordinates (55 FR

3494, February 1, 1990, and 55 FR 32681, August 10, 1990).

For example (hypothetical), for Turning Point 12 on the U.S.-Canada Maritime

Boundary, the NAD 83 coordinate equivalents would be depicted on NAD 83

OPD NL 19-12 as:

T.P. 12 (44E49'43.91280"N 66E57'55.05356W" Transformed).

3.2.4. Provisional Maritime Boundary Note. In 1989/90 the DOS approved an

explanatory note for inclusion on NAD 27 OPD collars relative to provisional

international maritime boundaries. NAD 83 OPD's depicting provisional international

maritime boundaries, will included the DOS approved collar note:

The United States-[name of country] maritime boundary depicted here is

provisional, pending the entry into force of applicable boundary delimitation

agreements and, beyond 200 nautical miles, pending the delimitation of United

States continental shelf jurisdiction.

3.2.5. Exclusive Economic Zone (EEZ) Limit. NAD 83 OPD's will follow conventions

developed by MMS and DOS for NAD 27 OPD's containing the Exclusive Economic

Zone (EEZ) limit:

! OPD's will depict the cadastre for the full NAD 83 1E (of latitude) x 2E (of

longitude) or 1Ex3E OPD limit.

! OPD's will not depict the 200 nautical mile EEZ limit.

! The following note will be included on the OPD collar:

Although not shown, the 200 nautical mile Exclusive Economic Zone

(EEZ) limit lies within this diagram.

When the MSS geodesist has completed the ellipsoidal geometry-based programs for
 12 Graphic portrayal must be on only one datum, i.e., either NAD 27 or NAD 83. SOCBD's can depict boundaries

from both datums if transformed coordinates are used for one of them.

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B&B, TIMS, MMS and DOS will reevaluate the policy of not depicting the EEZ limit on

OPD's.

3.3. Supplemental Official OCS Block Diagram(s) (SOBD)

SOBD's are large-scale standard computational products which supplement OPD's. 

SOBD's graphically portray the final results of the computational process for boundaries

projected offshore from a baseline (e.g., the SSB) and cadastre blocks adjoining nonprojected international maritime boundaries (e.g., the U.S.-Canada Maritime Boundary

on OPD NL 19-12). Unlike the depiction of international maritime boundaries on OPD's

(Part II, section 3.2.3.), NAD 83 UTM coordinate equivalents will be used to compute

the SOBD's. (See Part II, section 4.3. for a discussion of coordinate equivalents.)

SOBD's identify the OPD name and number, block number, datum, previous

computation date, and planning area. They define the radius and types of boundaries

intersecting the block, coordinates for arc and tangent segment offshore intersections,

contributing baseline point coordinates, UTM "X" and "Y" coordinates of the block, areal

measurements within the block, and ("for the Director, MMS") approval signature and

date.

3.4. Supplemental Official Composite Block Diagram(s) (SOCBD)

SOCBD's are specialized computational products which supplement OPD's and

SOBD's. These large-scale diagrams are portrayed on a format similar to the SOBD. 

They show ambulatory boundary changes through time within a single block, usually on

the same datum12. Baseline ambulation occurs in areas where the baseline has not

been fixed by court decree or in areas where straight baseline and other contention

issues have been resolved.

For example, SOCBD's are needed for areas like NR 06-03, Block 423 in the Beaufort

Sea Planning Area. Between the computations for the SOBD's dated 6/4/82 and 2/2/88,

the State revised their straight baseline contentions, eliminating the baseline contention

which affected this block, and a new hydrographic survey was completed, leading to a

landward movement of the computational baseline and associated seaward projected

boundaries. As there were State leases adjoining the 6/4/82 SSB, the Federal

Government did not re-lease any of the former State areas that were within the Federal

'8(g) Zone' after the 2/2/82 computations. Prior to Sale 124 in 1991, leases adjoining

the 6/4/82 SSB were relinquished. A SOCBD depicting the 1982 and 1988 projected

seaward boundaries defined areas (of less than 12 hectares) within the Federal '8(g)

Zone' which could potentially be developed into a bidding unit.
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3.4.1. OCS Regions. The OCS regions must specifically request SOCBD production,

provide the MSS with all relevant source materials needed to develop the SOCBD's,

and identify a point of contact with whom the MSS can work directly. SOCBD depiction

of lease or land status information is an OCS regional responsibility. Blocks depicting

lease or land status information must be approved (signed and dated) by the

appropriate OCS Regional Director.

3.4.2. Office of International Activities and Marine Minerals (INTERMAR). INTERMAR

must specifically request SOCBD production, provide the MSS with all relevant source

materials needed to develop the SOCBD's, and identify a point of contact with whom the

MSS can work directly. SOCBD depiction of lease or land status information is an OCS

regional responsibility. Blocks depicting lease or land status information must be

approved (signed and dated) by the appropriate OCS Regional Director.

3.4.3. Mapping & Survey Staff (MSS). Upon formal request of an OCS region or

INTERMAR, the MSS will develop SOCBD's. They will depict the coordinates of the

intersection(s) of the ambulatory boundaries, areal measurements for the resulting

parcels of land, and approval signature and date. SOCBD's are intended for use with

SOBD's and will not show coordinates for the projected boundary arc and tangent

segment intersections, contributing baseline point coordinates, nor projected boundary

intersections with the block boundary as depicted on the "parent" SOBD's. SOCBD's,

as developed by the MSS, will not depict lease or land status information; this

information may be added by the OCS regions as indicated in Part II, sections 3.4.1.

and 3.4.2.

3.5. Supplemental Official Lease Diagram(s) (SOLD)

SOLD's are specialized computational products which supplement OPD's and SOBD's. 

MSS will use PLUD's annotated by OCS regional leasing specialists to develop SOLD's. 

Like SOBD's, SOLD's are intended to be used as stand-alone lease descriptions in the

lease instrument. They reflect official NAD 83 coordinates and areal measurements of

bidding units. NAD 27 lease instruments reflect a NAD 27 leasehold's official

description (see Part II, section 4.3.); SOLD's will reflect the NAD 83 coordinate

equivalents of appropriate portions of NAD 27 leaseholds lying within an NAD 83

cadastre block. (See Part II, section 10.) Until a NAD 27 leasehold is terminated,

relinquished or expires, the official description of the boundary between adjoining NAD

27 and NAD 83 leaseholds will be the NAD 27 lease description. (See Part II, section

4.3.6.)

3.5.1. OCS Regions. OCS Regions must specifically request SOLD production and

work with MSS to develop PLUD's as outlined in Part II, section 3.6.1. Prior to the

Chief, MSS signing completed SOLD's for the Director, MMS, the appropriate OCS

region will review, verify, and approve the portrayed NAD 27 leasehold information.
 13 When this document was written, OCSIS was being converted into several major components of TIMS. Rather

than cite each component, throughout the remainder of this document, OCSIS and the TIMS components being

derived from OCSIS, will be referred to as "TIMS(O)."

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3.5.2. Office of International Activities and Marine Minerals (INTERMAR). INTERMAR

must specifically request SOLD production and work with MSS to develop PLUD's (as

outlined in Part II, section 3.6.2.). Prior to the Chief, MSS signing completed SOLD's for

the Director, MMS, INTERMAR and the appropriate OCS region must review, verify,

and approve the portrayed NAD 27 leasehold information.

3.5.3. Offshore Systems Center (OSC). OSC will modify the B&B, TIMS computational

system to incorporate needed output requirements for SOLD's.

3.5.4. Mapping & Survey Staff (MSS). MSS will use PLUD's annotated by an OCS

regional leasing specialist to develop the SOLD's. MSS will use B&B, TIMS to compute

coordinates and areal measurements to SOBD accuracy. SOLD's will be signed for the

Director, MMS, by the Chief, MSS, after OCS regional (and, if necessary, INTERMAR)

approval/verification of portrayed NAD 27 leasehold information.

3.6. Plot Unit Diagram(s) (PLUD)

PLUD's are internal working documents used to develop SOLD's. Using the NAD 83

B&B, TIMS database and NAD 27 leasing information from the Outer Continental Shelf

Information System (OCSIS)13, an OCS regional leasing specialist detailed to the MSS

will produce print screens through the B&B, TIMS production process. (See Part I,

section 2.3.4.) The OCS regional leasing specialist will annotate the PLUD's to indicate

how irregular portions resulting from NAD 27 leaseholds adjoining unleased areas on

the NAD 83 cadastre are to be combined to form bidding units.

3.6.1. OCS Regions. OCS Regions must specifically request PLUD production and

work with MSS to develop them. The OCS regions will:

! Detail an OCS regional leasing specialist to MSS to develop the PLUD

portrayal of bidding units.

! Update and maintain the TIMS(O) database to reflect the most current

leasehold information prior to PLUD production.

3.6.2. Office of International Activities and Marine Minerals (INTERMAR). INTERMAR

must specifically request PLUD production and work with MSS to develop them. In

addition, INTERMAR will:

! Arrange for an OCS regional leasing specialist from the appropriate OCS

region to be detailed to MSS to develop the PLUD portrayal of bidding units.
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! Arrange for the appropriate OCS region to update the TIMS(O) database to

reflect the most current leasehold information prior to PLUD production.

3.6.3. Mapping & Survey Staff (MSS). MSS will:

! Coordinate PLUD production with the OCS regions and INTERMAR.

! Provide B&B, TIMS/PLUD training to OCS regional leasing specialists prior

to PLUD production.

3.7. Summary of MMS NAD 83 Cadastre-related Products

3.7.1. Standard Computational Products. The Mapping & Survey Staff (MSS) will depict

the NAD 83 cadastre on two standard computational products--OPD's and SOBD's:

! OPD's (Official Protraction Diagrams) are the base documents which

are supplemented by all other MMS cadastre-related products. They

depict a metric grid, with full grid blocks being 4800-by-4800 meters

throughout the OCS and areal measurements for partial blocks along

UTM zone boundaries.

! SOBD's (Supplemental Official OCS Block Diagrams) are individual

cadastre block diagrams which identify the OPD name and number,

block number, datum, previous computation date, planning area,

radius and types of boundaries intersecting the block, coordinates for

arc and tangent segment offshore intersections, contributing baseline

point coordinates, UTM "X" and "Y" coordinates of the block, areal

measurements within the block, and ("for the Director, MMS")

approval signature and date.

3.7.2. Specialized Computational Products. Upon OCS regional or INTERMAR request,

the MSS will depict the NAD 83 cadastre on two specialized computational products--

SOCBD's and SOLD's:

! SOCBD's (Supplemental Official Composite Block Diagrams) are

supplements to SOBD's. These SOBD-like diagrams portray

ambulatory boundary changes through time, within a single block,

and usually on the same datum and identify boundary intersections

and resultant areal measurements.

! SOLD's (Supplemental Official Lease Diagrams), a SOBD-like

diagram, are developed from PLUD's, and are intended for use as

stand-alone lease instrument descriptions when a NAD 83 cadastre

block contains a NAD 27 leasehold's. (PLUD's--Plot Unit Diagrams

are internal working documents which have been annotated by an
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OCS regional leasing specialist to indicate how irregular portions

resulting from NAD 27 leaseholds adjoining unleased areas on the

NAD 83 cadastre are to be combined to form bidding units.)

3.8. Historical Record

The MSS will:

! Maintain a historical record of each NAD 83 OPD in hardcopy,

archival quality, format.

! Maintain a historical record of each NAD 83 SOBD, SOCBD, and SOLD in

both digital (B&B, TIMS) and hardcopy formats.

! Maintain a historical record of the final NAD 27 OPD's prior to conversion of

planning areas to NAD 83 in hardcopy, archival quality, format.

! Maintain a historical record of each pre-B&B, TIMS computed NAD 27

SOBD and SOCBD in hardcopy format.

! Maintain a historical record of each B&B, TIMS computed NAD 27 SOBD

and SOCBD in both digital and hardcopy formats.

4. DATUM TRANSFORMATIONS

The MMS will use the FGCS approved procedures for obtaining NAD 83 coordinates for

NAD 27 positions. In descending order of accuracy, these three methods are: 

! Survey the NAD 27 positions on NAD 83.

! Perform a simultaneous adjustment for all NAD 27 positions utilizing

original survey observations.

! Transform NAD 27 coordinate values using the North American

Datum Conversion (NADCON) transformation software.

4.1. Transformation Software

For most purposes, the MMS will use the third option to obtain NAD 83 equivalents for

NAD 27 coordinates/positions. Through 55 FR 3493, February 1, 1990, the MMS

advised the public that the Agency would use the NGS developed software for this

purpose. In 56 FR 20020, May 1, 1991, the MMS specifically advised the public that the

federally-endorsed datum transformation computer software known as NADCON would
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be used to convert existing NAD 27-based cadastre coordinates into NAD 83

equivalents.

The first version of NADCON to fully satisfy MMS OCS requirements offshore of Alaska

and the conterminous U.S. is NADCON v2.00. The NGS officially released NADCON

v2.00 in July 1991, and was adopted as the Agency's standard NAD 27/83 datum

transformation software. With the introduction of the HARN's, this policy is being

modified to accommodate later versions of NADCON. (See Part II, section 3.1.5.)

The current version of NADCON (v2.10) and NADCON v2.00 produce identical NAD

27/NAD 83 (1986) transformation output from the same input. However, NADCON

v2.00 and the previous NADCON versions (e.g., v1.01 and v1.02) do not always

develop identical transformation output from identical input coordinates. It is, therefore,

the Agency's policy that:

! The NADCON version used must be identified on all transformed coordinates,

both hardcopy and digital data formats.

! Transformed coordinates developed by using earlier NADCON versions may

be used for planning purposes, if the NADCON version is known.

! NADCON v2.00 or later will be used for transformed coordinates and

computations released to the public or other agencies.

4.1.1. OCS Regions. Each OCS Regional Director will designate an OCS regional

NADCON liaison. The liaison will serve as the point of contact for the MSS geodesist

for the dissemination of NADCON and NADCON-related information within the OCS

region.

4.1.2. Mapping & Survey Staff (MSS). The MSS geodesist will be responsible for:

! Identifying and coordinating NADCON revisions with the NGS. 

! Distributing and maintaining the PC executable version of NADCON within the

Agency.

! Distributing and maintaining the NADCON source code within the Agency.

! Ensuring OSC receives revisions to the NADCON code.

4.1.3. Offshore Systems Center (OSC). OSC will be responsible for the incorporation of

NADCON into the Agency's national computer systems. When requested, OSC will

assist the OCS regions with incorporating NADCON into OCS regional computer

systems.
 14 Vincenty, T. (1988) "A Note on Approximate Transformations of Coordinates." Surveying and Mapping, 48, No.

3, pp. 207-211.

 15 Graff, D.R. (1988). "Coordinate Conversion from NAD 27 to NAD 83." Journal of Surveying Engineering, 114,

No.3, pp. 125-130.

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4.1.4. OPDC Supervisory Program Analyst. Through Federal Register notices, the

OPDC Supervisory Program Analyst will advise the public of MMS adoption of new

NADCON versions.

4.2. NAD 83 Coordinate Equivalent Values for Non-NAD 83 International 

Maritime Boundaries

The conversion of non-NAD 83 international maritime boundaries (e.g. U.S.-Canada

Maritime Boundary in the Gulf of Maine) to NAD 83 will be determined on a boundary by

boundary basis. The MSS geodesist will determine the most appropriate method

(transformation, recomputation, both, etc.) for calculating the NAD 83 coordinate

equivalents, and the Chief, MSS will coordinate with DOS to ensure acceptability of the

procedures and coordinates. (See Part II, sections 4.3.4. and 6.)

4.3. Leasehold and Boundary Integrity When Transforming

The MMS affirms that an OCS lessee's rights issued under a NAD 27 legal descriptions

will continue to be protected as warranted under that description (55 FR 3493, February

1, 1990). However, the procedure for portraying NAD 27 leases on the NAD 83

cadastre and developing NAD 83 coordinate equivalents and areal measurements for

the leases can be complex:

! "There is no rigorous mathematical method for transformation between

such systems as NAD 27 and NAD 83... The most that we can achieve ...

is to make sure that the fixed coordinates in the new system remain the

same as published and that the shapes of geometric figures within the

network are preserved as much as possible. Beyond that all efforts are

fruitless."14

! "[NAD 27 and NAD 83] differ systematically because of a change in the

reference ellipsoid and randomly because of imperfections in either system,

known distortions in NAD 27, and the inclusion of many new measurements

in the NAD 83 adjustment."15

! Both straight lines and arcs in NAD 27 become non-mathematically

definable curves when transformed and portrayed in NAD 83. (See Part II,

Appendix B.)
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! The original NAD 27 radius between projected boundary intersections and

the baseline is not maintained during the transformation process. (For

example, a NAD 27 radius of 5556 meters will be 5556 meters plus or

minus a small amount.)

In addition, there are two major concerns. First, the procedure should be

straightforward and simple, requiring neither special knowledge nor a significant amount

of training for understanding and use. Second, industry, coastal States, and other

Federal agencies must be able to replicate MMS computations without specialized

software and/or equipment.

As discussed in Part II, Appendix B, to simplify the transformation process for NAD 27

leaseholds and to ensure that industry, the coastal States, and others can replicate the

MMS computations, the MMS will consider:

! Straight lines on NAD 27 leaseholds and boundaries to be straight lines on

NAD 83.

! Arcs on NAD 27 leaseholds to be arcs of the same radius on NAD 83.

The procedures outlined in Part II, sections 4.3.1. through 4.3.6. are specific conditions

which further explain the process to be used by MMS to maintain NAD 27 leasehold and

boundary integrity.

4.3.1. Case 1: Blocks Leased Under NAD 27. On the exterior block boundary, the

maximum distance over which a straight line may be considered to connect transformed

coordinate pairs is between the block's corners (e.g., 4800 meters on the metric UTM

grid system in the Alaska OCS Region and 15,840 feet on the corrupted English UTM

system in the Gulf of Mexico OCS Region). However, if there are other intersections

with the block boundary (SSB, Limit of "8(g) Zone" Boundary, adjacent block corners,

etc.), then they become the limiting factor for assuming straight lines.

Example: On Figure 4, assume that Block 78, LM 9A is a NAD 27 leasehold. 

It is described by block corners D, E, H, and K. On the NAD 83 cadastre, a

straight line may be assumed between transformed corners D-E. However,

between corners D-K there are two intersections--intersection C with an

adjacent block corner and intersection n with the Limit of "8(g) Zone"

Boundary. These two intersections become the limiting factors for assuming

straight lines between block corners D-K. Straight lines may be assumed only

between transformed intersections D-n, n-C, and C-K.

On the interior of the block, all boundaries will be transformed. Straight lines on NAD 27

will be maintained as straight lines on NAD 83; and circular curves on NAD 27 will be

maintained as circular curves of the appropriate radius on NAD 83.

Example: On Figure 4, assume that Block 77, LM 9A is a NAD 27 leasehold. 
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It is described by block corners E, F, G, and H and contains the Limit of "8(g)

Zone" Boundary with intersections o, p, q, and r. On the NAD 83 cadastre,

these intersections would be transformed and the intersections connected with

either a straight line for a tangent segment or a circular curve of the

appropriate radius for an arc segment.

4.3.2. Case 2: Ambulatory Boundaries. Ambulatory NAD 27 projected offshore

boundaries will be recomputed on NAD 83 after the projected boundary's baseline has

been transformed or redefined on NAD 83. When these boundaries intersect a NAD 27

leasehold, the recomputed projected boundary will intersect and terminate on the

exterior block boundary of the leasehold. When the lease is terminated, relinquished or

expires, the block will be redefined on NAD 83 and the recomputed projected boundary

used.

Example: On Figure 4, assume that Block 77 and Block 78, LM 9A are NAD

27 leaseholds. The blocks are described respectively by block corners E-F-GH and D-E-H-K. As the blocks are leaseholds, Case 1 applies within the block

boundaries. However, outside of the leaseholds the recomputed Limit of "8(g)

Zone" Boundary terminates on the exterior of the leaseholds, causing a

temporary offset of the projected boundary as illustrated in the enlargements

for intersections n and r.

4.3.3. Case 3: U.S. Supreme Court Decreed Boundaries. If a boundary projected

offshore from a U.S. Supreme Court decreed NAD 27 baseline (e.g., the court-decreed

baseline for the State of Mississippi) is not contained within a leased block, the baseline

from which the boundary is projected will be transformed and the projected boundary

recomputed on NAD 83.

Example: On Figure 4, assume that the Limit of "8(g) Zone" Boundary has

been projected from a U.S. Supreme Court decreed NAD 27 baseline. The

decreed baseline coordinates would be transformed and the projected

boundary recomputed. Inside the leasehold, Case 1 applies. Outside of the

leasehold the results would be the same as for Case 2--the recomputed Limit

of "8(g) Zone" Boundary terminates on the exterior of the leaseholds, causing

a temporary offset of the projected boundary.

Both the baseline and the SSB for the State of Louisiana have been decreed by the

U.S. Supreme Court. Transformation of the decreed NAD 27-based coordinates for

these two lines will negate the three Admiralty/Imperial mile relationship between them. 

Thus, conversion of Louisiana's baseline and SSB will require special

considerations/procedures to be developed later. Development of these procedures

may require the MSS to work with the Department of Justice and the issuance of a

Supplemental Decree.
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4.3.4. Case 4: International Maritime Boundaries. NAD 27-referenced international

maritime boundaries which have been established by international agreement, treaty,

decisions of the World Court, etc., normally will be converted to NAD 83 as outlined in

Part II, sections 4.2. and 6. The resulting NAD 83 boundary coordinate equivalents will

be connected using the method (geodesic lines, rhumb lines, etc.) indicated in the

original document establishing the boundary.

Example: The NAD 27 coordinates for the U.S.-Canada boundary in the Gulf

of Maine will be transformed to NAD 83 equivalents. The NAD 83 coordinate

equivalent intersections would be connected using the method described in

the original document establishing the boundary.

4.3.5. Case 5: Subdividing Irregular Portions to Create Bidding Units. Irregular portions

result from NAD 27 leaseholds adjoining unleased areas on the NAD 83 cadastre. As

used by the MMS, an irregular portion is the unleased area in a NAD 83 cadastre block

lying between a transformed NAD 27 lease boundary and a NAD 83 block boundary.

Example: On Figure 4, the area outside the NAD 27 leasehold in the NAD 83

block bounded by the following coordinates is an irregular portion:

NW corner X=264 800, Y=3 192 000

NE corner X=269 600, Y=3 192 000

SE corner X=269 600, Y=3 187 200

SW corner X=264 800, Y=3 187 200

At the Regional Director's discretion, these irregular portions may be added to other

adjoining unleased cadastre blocks to create a bidding unit. (See Part II, sections 3.5.

and 3.6.) When the subdivision of an irregular portion into two or more fractional parts

is necessary, the MMS will use established surveying procedures for the subdivision of

fractional sections.

Example: On Figure 4, assume it is necessary to subdivide the 404.804000

hectare irregular portion into two fractional parts at corner F. Three main options

are:

! A line from corner F to the southeast corner of the

 block.

! An extension of transformed line E-F (or F-G).

! A line running grid north-south (or grid east-west) from

 corner F.

The MMS will use option three to subdivide irregular portions into fractional parts. 

This option simplifies the computational and replication procedures.
 16 The orphan datum for St. Matthew, Hall, and Pinnacle Islands has not been incorporated into either NAD 27 or

NAD 83. Also see Part II, Section 6.

 17 NADCON does not differentiate between NAD 27 and orphan datum coordinates in the input. Output Format 1,

identifies the datum name used by NADCON; output Format 2 does not.

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4.3.6. Form MMS-2005. When NAD 83 irregular portions adjoining NAD 27 leaseholds

are leased, Form MMS-2005 ("Oil and Gas Lease of Submerged Lands Under the Outer

Continental Shelf Lands Act") must reflect: (1) that the boundary description between

the NAD 27 and NAD 83 leaseholds is the NAD 27 lease description until such time as

the NAD 27 leasehold is terminated, relinquished or expires; and (2) the NADCON

version used to determine NAD 83 coordinate equivalents. (See Part II, section 3.5.)

4.4. Orphan Datum Transformations

NADCON v2.00 and v2.10 (see Part II, section 3.1.5.) perform most NAD 27 to NAD 83

coordinate transformations using the CONUS.LAS & CONUS.LOS data files in the

Atlantic, Gulf of Mexico, and Pacific OCS Regions and the ALASKA.LAS &

ALASKA.LOS data files in the Alaska OCS Region. The latitude and longitude limits for

these data files are:

Data File Latitude Longitude

CONUS 20EN-50EN 063EW-131EW

ALASKA 46EN-77EN 128EW-194EW

Within all OCS regions except the Gulf of Mexico, orphan datums--local datums,

exclusively covering relatively small areas--existed when the U.S. adopted NAD 83. For

a variety of reasons, these datums, such as the St. Lawrence Datum in Bering Sea, the

Puerto Rico and Virgin Islands Datum in the Caribbean Sea, and the Old Hawaiian

Datum in the Pacific Ocean were never tied to, nor incorporated into, NAD 27.

Historically, the U.S. has had many orphan datums (e.g., the Valdez Datum), most of

which were incorporated into NAD 27 long before the U.S. adoption of NAD 83. When

the U.S. adopted NAD 83, the parameters necessary to transform most remaining

orphan datum coordinates directly to NAD 83 were determined, thus by-passing their

incorporation into NAD 2716.

The following orphan datums co-existed with NAD 27 at the time the U.S. adopted NAD

83. The latitude and longitude limits below define the areas where NADCON, in

standard configuration for an OCS region, considers any input coordinate to be on the

orphan datum17 when transforming from NAD 27 to NAD 83:
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Alaska OCS Region

Datum Latitude Longitude

St. George 56EN-57EN 169EW-170EW

St. Lawrence 62EN-64EN 168EW-172EW

St. Matthew See Part II, Section 6

 St. Paul 57EN-58EN 169EW-171EW

Atlantic OCS Region

Datum Latitude Longitude

Puerto Rico/V.I. 17EN-19EN 064EW-068EW

Pacific OCS Region

Datum Latitude Longitude

Old Hawaiian 18EN-23EN 154EW-161EW

As currently defined, NADCON's CONUS data files do not overlap the Caribbean Sea

and Pacific Ocean orphan datums. This means that although orphan datum to NAD 83

and NAD 83 to orphan datum coordinate transformations can be performed, NAD 83 to

NAD 27 and NAD 27 to NAD 83 transformations cannot. If actual NAD 27 coordinates

are to be transformed, or are needed, NADCON will have to be revised or another

transformation procedure used.

In the Alaska OCS Region, however, the Alaska data files do overlap the area of the

orphan datums. Thus special, standardized transformation procedures within the

orphan datum limits must be used.

4.4.1. Orphan Datum Transformation Procedure 1--To Obtain NAD 27 Coordinates

From Orphan Datum Coordinates.

1. With NADCON in "standard configuration" for the MMS Alaska OCS Region

(i.e., STGEORGE.LAS & STGEORGE.LOS, STPAUL.LAS & STPAUL.LOS,

and STLRNC.LAS & STLRNC.LOS data files in the NADCON program

directory), enter the orphan datum coordinates into the program and

transform them into their NAD 83 coordinate equivalents. (See Figure 5.)

2. Temporarily remove the appropriate data files (STGEORGE.LAS &

STGEORGE.LOS, STPAUL.LAS & STPAUL.LOS, or STLRNC.LAS &

STLRNC.LOS) from the NADCON program directory. This can be done by

(1) deleting the appropriate data files, (2) moving the appropriate data files to

another directory, or (3) renaming the data files (e.g., change

STGEORGE.LAS and STGEORGE.LOS to STGEORGE.LA and

STGEORGE.LO, respectively.)

3. Enter the NAD 83 coordinate equivalents into NADCON and transform them

into NAD 27 coordinate equivalents. (NADCON will perform the

transformations using the ALASKA.LAS & ALASKA.LOS data files.)
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PART II –Technical Aspects of Implementation

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4. Return the NADCON program directory to its original configuration. (How

this is done depends upon how step 2 was performed.)

6444444444444444444444444444444444444444444444444444444444444444444444444444444444

7

5 . Current <Dir> | .. Parent <Dir> 

 5

5 ALASKA .LAS 530,000 04-12-91 01:30p | ALASKA .LOS 530.000 04-12-

91 01:33p 5

5 AREA .PAR 26 03-04-91 02:07p | NADCON .EXE 91,618 06-24-

91 09:44a 5

5 NADGRD .EXE 73,164 08-29-90 08:32a | NADGRD .FOR 55,141 09-04-

90 01:17p 5

5 README .200 13,594 07-03-91 10:31a | README .GRD 12,208 09-04-

90 03:14p 5

5 STGEORGE.LAS 30,256 01-02-90 01:19p | STGEORGE.LOS 30,256 01-02-

90 01:19p 5

5 STLRNC .LAS 13,776 01-02-90 02:19p | STLRNC .LOS 13,776 01-02-

90 02:20p 5

5 STPAUL .LAS 3,696 01-02-90 02:21p | STPAUL .LOS 3,696 01-02-

90 02:21p 5

9444444444444444444444444444444444444444444444444444444444444444444444444444444444

8

Figure 5. Standard NADCON v2.00 directory configuration for the MMS

Alaska OCS Region.

4.4.2. Orphan Datum Transformation Procedure 2--To Obtain NAD 83 Coordinates

From Actual NAD 27 Coordinates.

1. Temporarily remove the appropriate data files (STGEORGE.LAS &

STGEORGE.LOS, STPAUL.LAS & STPAUL.LOS, or STLRNC.LAS &

STLRNC.LOS) from the NADCON program directory. This can be done by

(1) deleting the appropriate data files, (2) moving the appropriate data files to

another directory, or (3) renaming the data files (e.g., change

STGEORGE.LAS and STGEORGE.LOS to STGEORGE.LA and

STGEORGE.LO, respectively.)

2. Enter the NAD 27 coordinates into NADCON and transform them into their

NAD 83 coordinate equivalents.

3. Return the NADCON program directory to its original configuration. (How

this is done depends upon how step 1 was performed.)

5. MMS/GEOLOGICAL SURVEY (USGS) AGREEMENT

For NAD 83-based OPD's adjoining the shoreline, the MSS will utilize selective thematic

map layers from the USGS National Mapping Program 1:100,000- and 1:250,000-scale
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maps. OPD's which do not adjoin or contain landmass do not necessitate a cooperative

production effort. The main points of the ten year MMS/USGS Agreement, signed April

5, 1991, follow.

5.1. MMS/MSS Responsibilities

The MSS will:

! Provide the USGS, Rocky Mountain Mapping Center (RMMC) with a list of

OPD's and corresponding USGS, Defense Mapping Agency, and/or adjacent

country 1:250,000-scale maps in order of priority and proposed completion

dates. 

! Provide the USGS, RMMC with edited copies of the appropriate USGS maps

depicting features to be shown and/or deleted from the deliverable USGS

product.

! Arrange periodic meetings among technical staffs to discuss work status,

resolve technical issues related to NAD 83 conversion, and the mapping

products.

! Provide the USGS, RMMC with a stable base film positive or negative of the

finalized OPD's which depict the shoreline, as they are completed.

5.2. USGS Responsibilities

The USGS, RMMC will:

! Provide the MMS with copies of the appropriate USGS maps to be used to

depict features to be shown and/or deleted from on the deliverable USGS

product.

! Provide the MMS with one (1) emulsion up, 7 mil film positive for each map. 

The composite film positive will consist of the following: drainage plate

showing shoreline areas, rivers, and other hydrographic features;

hydrographic feature place names from both the "blue" and "black" separation

plates; and NAD 83 latitude and longitude grid ticks depicted at 15-minute

intervals.

Usually, the composite plates will follow the standard 1:250,000-scale USGS map

format. When a map does not follow the standard format (includes insets, e.g., Trinity

Islands; depicts areas beyond the neatlines, e.g., Teller; or the map uses a nonstandard neatline format, e.g., Unalaska), the features will be cast on a separate cell in

their correct locations.
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5.3. MMS/USGS, RMMC Joint Responsibilities

The exceptions noted above will be identified in a jointly developed MMS/USGS Annual

Work Plan (AWP). The MMS and the USGS, RMMC will begin preparing the AWP early

in the third quarter of the fiscal year (FY) so that it can be executed by the start of the

next FY. The AWP's may include, but are not limited to: definition of financial

arrangements; definition of cartographic products to be delivered or supplied; definition

of product standards and technical specifications; agency responsibilities; production

and delivery schedules; and the duration of the AWP.

6. DEPARTMENT OF STATE (DOS) COORDINATION

The DOS will be provided an opportunity to review MMS NAD 83 OPD's adjoining

international maritime boundaries. In addition to the graphic product review, DOS will

be afforded the opportunity to review transformed SOBD coordinates for the

international maritime boundaries. The Chief, MSS will coordinate DOS review and

ensure that the OPD's and SOBD's are available to the OCS regions by the established

dates.

7. ST. MATTHEW ISLAND

Although NAD 83 is the official horizontal datum for the U.S., several orphan datums are

still in use. Most are in the U.S. Pacific Dependencies (e.g., Guam); however, in

Alaska, St. Matthew Island along with neighboring Hall and Pinnacle Islands remain on

an orphan datum.

The NGS has indicated that they do not have sufficient horizontal control data to place

the island on either NAD 27 or NAD 83. This situation precludes:

! The accurate projection of the SSB and the Limit of "8(g) Zone" Boundary

seaward from the islands.

! The transformation of orphan datum coordinates to or from either NAD 27 or

NAD 83.

The MSS geodesist will continually evaluate potential cooperative agreements and

emerging technologies (e.g., kinematic aerial photography/Global Positioning System

(GPS) surveying) to find a cost effective method of placing the islands on NAD 83.

8. COMPUTATION OF PROJECTED MARITIME

BOUNDARIES BEYOND 12 NAUTICAL MILES
 18 Texas and the Gulf of Mexico side of Florida have a composite (historic and current) State Seaward Boundary of

three marine leagues (i.e., nine nautical or geographic miles). The Limit of "8(g) Zone" Boundary is three nautical or

geographic miles seaward of the State Seaward Boundary.

 19 This is not a need unique to NAD 83. There may also be a need to depict these maritime boundaries on NAD

27 OPD's in planning areas that are not scheduled for conversion to NAD 83 until late in the process.

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The computational programs currently used by the MSS to project boundaries seaward

from a baseline (e.g., the SSB), are based on planar geometry. These programs were

specifically designed for nearshore computations (3 to 6 nautical miles offshore), and at

12 nautical miles18 offshore, they have reached the limit of their computational accuracy.

For several years a need to compute maritime boundaries projected more than 12

nautical miles from a baseline (e.g., the 200 nautical mile EEZ Boundary and

moratorium and impact assistance lines) has been emerging.19 However, accurately

projecting boundaries beyond 12 nautical miles seaward from a baseline requires a

fundamental change in the computational algorithms--projections will have to be based

on the principles of ellipsoidal rather than planar geometry.

The MSS geodesist will provide the OSC with the ellipsoidal geometry algorithms and

technical documentation after the programs have been tested. The OSC and the MSS

should have the equidistant and ellipsoidal geometry-based programs completed,

tested, documented, and incorporated into B&B, TIMS six months later.
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9. APPENDIX A--NAD 83 OPD FORMAT

9.1. NAD 27 OPD/LM Formats

As discussed in Part I, Appendix A, there are five NAD 27 cadastres used on the OCS

offshore of the conterminous U.S. and Alaska. The uniqueness of each SPCSreferencing LM cadastre is illustrated in Figures 6 through 8 (followed by additional

cadastre attributes):

64444444444444444444444444444444444444444444444444444444444444444444444444447

5 +)))))0)))))0)))))0)))))0)))))0)))))0))))), 5

5 * 6 * 91 * 90 * 89 * 88 * 87 * 86 * 5

5 /)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 7 * 92 * 93 * 94 * 95 * 96 * 97 * 5

5 +)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 17 * 18 * 103 * 102 * 101 * 100 * 99 * 98 * 5

5 /)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 20 * 19 * 104 * 105 * 106 * 107 * 108 * 109 * 5

5 /)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 27 * 28 * 115 * 114 * 113 * 112 * 111 * 110 * 5

5 /)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 30 * 29 * 116 * 117 * 118 * 119 * 120 * 121 * 5

5 /)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 37 * 38 * 127 * 126 * 125 * 124 * 123 * 122 * 5

5 +)))))0)))))0)))))0)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 44 * 43 * 42 * 41 * 40 * 39 * 128 * 129 * 130 * 131 * 132 * 133 * 5

5 /)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 55 * 56 * 57 * 58 * 59 * 60 * 139 * 138 * 137 * 136 * 135 * 134 * 5

5 .)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))3)))))1 5

5 * 65 * 64 * 63 * 62 * 61 * 140 * 141 * 142 * 143 * 144 * 145 * 5

5 .)))))3)))0)2)0)))3)))0)2)0)))3)))0)2)0)))2)))))2)))))2)))))2)))))- 5

5 * 6 * 6 * 7 * 7 * 7 * 7 * 1 * 1 * 5

5 * 8 * 9 * 0 * 1 * 2 * 3 * 4 * 4 * 5

5 * * * * * * * 7 * 6 * 5

5 .)))2)))2)))2)))3)))2)0)2)))3)))2), 5

5 * 74 * 148 * 149 * 5

5 /)))))3)))))3)))))1 5

5 * 77 * 151 * 150 * 5

5 /)))))3)))))3)))))1 5

5 * 78 * 152 * 153 * 5

5 .)))))2)))))2)))))- 5

94444444444444444444444444444444444444444444444444444444444444444444444444448

Figure 6. Cadastre 1: Typical numbering scheme for Leasing Maps referencing the

Louisiana SPCS--LA Map No. 10 (Main Pass Area).

! Dimensions of LM's: unique to each LM.

! Number of columns of blocks: unique to each LM.

! Number of rows of blocks: unique to each LM.

! Area of full cadastre grid blocks: varies; usually between 4,999.967 and 5,760

acres.

! Starting LM cadastre block number: unique to each LM.
 aLiterally, “turning like an ox while plowing;” the numbering of successive rows of blocks on a cadastre from

right to left then left to right, etc.

32

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

! Block numbering scheme: generally boustrophedonica.

6444444444444444444444444444444444444444444444444444444444444444444444447

5 +))))0))))0))))H))))0))))0))))0))))0))))0))))0))))0)))), 5

5 777*1031*1032*103351034*1035* A-6* A-5* A-4* A-3* A-2* A-1* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3)))), 5

5 777*1040*1039*103851037*1036* A-7* A-8* A-9*A-10*A-11*A-12*A-13* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1052*1053*105451055*1056*A-20*A-19*A-18*A-17*A-16*A-15*A-14* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1061*1060*105951058*1057*A-21*A-22*A-23*A-24*A-25*A-26*A-27* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3)))), 5

5 777*1072*1073*107451075*1076*1077*A-34*A-33*A-32*A-31*A-30*A-29*A-28* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1083*1082*108151080*1079*1078*A-35*A-36*A-37*A-38*A-39*A-40*A-41* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1092*1093*109451095*1096*1097*A-48*A-47*A-46*A-45*A-44*A-43*A-42* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1103*1102*111051100*1099*1098*A-49*A-50*A-51*A-52*A-53*A-54*A-55* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1112*1113*111451115*1116*1117*A-62*A-61*A-60*A-59*A-58*A-57*A-56* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3))))- 5

5 777*1124*1123*112251121*1120*1119*1118*A-63*A-64*A-65*A-66*A-67* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1132*1133*113451135*1136*1137*1138*A-72*A-71*A-70*A-69*A-68* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1145*1144*114351142*1141*1140*1139*A-73*A-74*A-75*A-76*A-77* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3)))), 5

5 777*1152*1153*115451155*1156*1157*1158*A-83*A-82*A-81*A-80*A-79*A-78* 5

5 /))))3))))3))))O))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 777*1165*1164*116351162*1161*1160*A-84*A-85*A-86*A-87*A-88*A-89*A-90* 5

5 .))))2))))2))))O))))2))))2))))2))))2))))2))))2))))2))))2))))2))))- 5

5 777 TEX Map No. 17V6TEX Map No. 1A 5

9444444444444444444444444444444444444444444444444444444444444444444444448

Figure 7. Cadastre 2: Typical numbering scheme for Leasing Maps referencing the

Texas SPCS--(portion) TEX Map No.1 (South Padre Island Area) and TEX Map No. 1A

(South Padre Island Area East Addition).

! Dimensions of LM's: unique to each LM.

! Number of columns of blocks: unique to each LM.

! Number of rows of blocks: unique to each LM.

! Area of full cadastre grid blocks: 5,760 acres.

! Starting LM cadastre block number: unique to each LM.

! Block numbering scheme: generally boustrophedonic. 6444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444447

5 R84W R80W R75W R72W 5
33

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

5+))))0))))0))))0))))0))))0))))0))))0))))0))))0))))0))))0))))0)))), 5

5*2584*2583*2582*2581*2580*2579*2578*2577*2576*2575*2574*2573*2572*T25N 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*2484*2483*2482*2481*2480*2479*2478*2477*2476*2475*2474*2473*2472*R71W 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3)))), 5

5*2384*2383*2382*2381*2380*2379*2378*2377*2376*2375*2374*2373*2372*2371* R69W 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))0)))), 5

5*2284*2283*2282*2281*2280*2279*2278*2277*2276*2275*2274*2273*2272*2271*2270*2269*T22N 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*2184*2183*2182*2181*2180*2179*2178*2177*2176*2175*2174*2173*2172*2171*2170*2169* 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*2084*2083*2082*2081*2080*2079*2078*2077*2076*2075*2074*2073*2072*2071*2070*2069*T20N 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*1984*1983*1982*1981*1980*1979*1978*1977*1976*1975*1974*1973*1972*1971*1970*1969* 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*1884*1883*1882*1881*1880*1879*1878*1877*1876*1875*1874*1873*1872*1871*1870*1869* 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*1784*1783*1782*1781*1780*1779*1778*1777*1776*1775*1774*1773*1772*1771*1770*1769* 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*1684*1683*1682*1681*1680*1679*1678*1677*1676*1675*1674*1673*1672*1671*1670*1669* 5

5/))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5*1584*1583*1582*1581*1580*1579*1578*1577*1576*1575*1574*1573*1572*1571*1570*1569*T15N 5

5.))))2))))2))))2))))2))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 R84W R80W*1479*1478*1477*1476*1475*1474*1473*1472*1471*1470*1469* 5

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 *1379*1378*1377*1376*1375*1374*1373*1372*1371*1370*1369* 5

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 *1279*1278*1277*1276*1275*1274*1273*1272*1271*1270*1269* 5

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 *1179*1178*1177*1176*1175*1174*1173*1172*1171*1170*1169* 5

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 T10N*1079*1078*1077*1076*1075*1074*1073*1072*1071*1070*1069*T10N R65W 5 

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))0))))0))))0)))), 5

5 * 979* 978* 977* 976* 975* 974* 973* 972* 971* 970* 969* 968* 967* 966* 965*6665

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 * 879* 878* 877* 876* 875* 874* 873* 872* 871* 870* 869* 868* 867* 866* 865*6665

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 * 779* 778* 777* 776* 775* 774* 773* 772* 771* 770* 769* 768* 767* 766* 765*6665

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 * 679* 678* 677* 676* 675* 674* 673* 672* 671* 670* 669* 668* 667* 666* 665*6665

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 T5N* 579* 578* 577* 576* 575* 574* 573* 572* 571* 570* 569* 568* 567* 566* 565*6665

5 /))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))3))))1 5

5 T4N* 479* 478* 477* 476* 475* 474* 473* 472* 471* 470* 469* 468* 467* 466* 465*6665

5 .))))2))))2))))2))))2))))2))))2))))2))))2))))2))))2))))2))))2))))2))))2))))- 5

5 R79W R75W R70W R65W 5

9444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444448

Figure 8. Cadastre 3: Typical numbering scheme for Leasing Maps referencing

the California SPCS--(portion) CAL Map No. 6E (Channel Islands Area).

! Dimensions of LM's: unique to each LM.

! Number of columns of blocks: unique to each LM.

! Number of rows of blocks: unique to each LM.

! Area of full cadastre grid blocks: 5,760 acres.

! Starting LM cadastre block number: unique to each LM.

! Block numbering scheme: township and range.Although each LM is unique

relative to the SPCS cadastre grid, depiction of the cadastre grids, information

portrayed on the cadastre grids, and information contained in the LM collar is

standardized:
34

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

! LM's use the Lambert projection referencing the Clarke 1866 spheroid.

! The SSB (generally three geographical miles or three marine leagues, as

appropriate for the particular coastal State) and the "Limit of '8(g) Zone'"

(generally three geographical miles beyond the SSB) are depicted from

computations based on principles outlined in the Law of the Sea Convention.

! Non-projected maritime boundaries are depicted as stipulated in the treaty,

international agreement, court decree, etc. which established the boundary.

! Areal measurements and distances for partial cadastre grid blocks adjoining

OPD/LM interfaces are depicted, usually to two decimal places.

! Collar notes and diagrams identify a SPCS's point of origin, the LM's Federal

approval date, dates of previous LM editions, scale, adjoining LM's and OPD's,

latitude and longitude, caveats, and other relevant information.

! Areal measurements for Federal and State land ownership, projected

boundary coordinates, and computational baseline coordinates for cadastre

blocks adjoining the SSB and the Limit of "8(g) Zone" are portrayed on

SOBD's.

Two additional cadastres, Cadastres 4 and 5, both based on the UTM grid and

projection system, are portrayed on OPD's. Cadastre 4, using a corrupted UTM grid

and English coordinates and areal measurements (feet and acres, respectively) is

utilized in those portions of the Gulf of Mexico OCS Region not covered by LM's. (See

Part I, Appendix A.) Cadastre 5, a completely metric UTM cadastre, is used in areas of

the Pacific OCS Region not covered by LM's and throughout the entire Alaska and

Atlantic OCS Regions.

The format for Cadastre 4 OPD's is:

! Dimensions of OPD's: 1E (of latitude) x 2E (of longitude).

! Number of columns of blocks: 44 columns of 15,840-by-15,840 feet blocks.

! Number of rows of blocks: 23 (or as necessary 24) rows of 15,840-by-15,840

feet blocks.

! Area of full cadastre grid blocks: 5,760 acres.

! Starting OPD block number: Block number 1 in column 1, row 1 (usually).

! Block numbering scheme: See Figure 9.
35

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

64444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L4444447

5Column * 1 * 2 666 5 666 10 666 15 666 20 666 25 666 30 666 35 666 40 666 44 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 Row 1 * 1 * 2 * 5 * 10 * 15 * 20 * 25 * 30 * 35 * 40 * 44 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 2 * 45 * 46 * 49 * 54 * 59 * 64 * 69 * 74 * 79 * 84 * 88 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 3 * 89 * 90 * 93 * 98 * 103 * 108 * 113 * 118 * 123 * 128 * 132 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 4 * 133 * 134 * 137 * 142 * 147 * 152 * 157 * 162 * 167 * 172 * 176 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 5 * 177 * 178 * 181 * 186 * 191 * 196 * 201 * 206 * 211 * 216 * 220 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 6 * 221 * 222 * 225 * 230 * 235 * 240 * 245 * 250 * 255 * 260 * 264 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 7 * 265 * 266 * 269 * 274 * 279 * 284 * 289 * 294 * 299 * 304 * 308 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 8 * 309 * 310 * 313 * 318 * 323 * 328 * 333 * 338 * 343 * 348 * 352 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 9 * 353 * 354 * 357 * 362 * 367 * 372 * 377 * 382 * 387 * 392 * 396 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 10 * 397 * 398 * 401 * 406 * 411 * 416 * 421 * 426 * 431 * 436 * 440 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 11 * 441 * 442 * 445 * 450 * 455 * 460 * 465 * 470 * 475 * 480 * 484 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 12 * 485 * 486 * 489 * 494 * 499 * 504 * 509 * 514 * 519 * 524 * 528 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 13 * 529 * 530 * 533 * 538 * 543 * 548 * 553 * 558 * 563 * 568 * 572 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 14 * 573 * 574 * 577 * 582 * 587 * 592 * 597 * 602 * 607 * 612 * 616 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 15 * 617 * 618 * 621 * 626 * 631 * 636 * 641 * 646 * 651 * 656 * 660 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 16 * 661 * 662 * 665 * 670 * 675 * 680 * 685 * 690 * 695 * 700 * 704 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 17 * 705 * 706 * 709 * 714 * 719 * 724 * 729 * 734 * 739 * 744 * 748 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 18 * 749 * 750 * 753 * 758 * 763 * 768 * 773 * 778 * 783 * 788 * 792 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 19 * 793 * 794 * 797 * 802 * 807 * 812 * 817 * 822 * 827 * 832 * 836 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 20 * 837 * 838 * 841 * 846 * 851 * 856 * 861 * 866 * 871 * 876 * 880 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 21 * 881 * 882 * 885 * 890 * 895 * 900 * 905 * 910 * 915 * 920 * 924 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 22 * 925 * 926 * 929 * 934 * 939 * 944 * 949 * 954 * 959 * 964 * 968 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 23 * 969 * 970 * 973 * 978 * 983 * 988 * 993 * 998 * 1003 * 1008 * 1012 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 24 * 1013 * 1014 * 1017 * 1022 * 1027 * 1032 * 1037 * 1042 * 1047 * 1052 * 1056 5

94444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N4444448

Figure 9. Cadastres 4 and 5: Typical numbering scheme for NAD 27 Official

Protraction Diagrams 44 cadastre grid blocks wide.
36

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

64444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L4444447

5Column * 1 * 2 666 5 666 10 666 15 666 20 666 25 666 30 666 35 666 40 666 45 666 47 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 Row 1 * 1 * 2 * 5 * 10 * 15 * 20 * 25 * 30 * 35 * 40 * 45 * 47 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 2 * 48 * 49 * 52 * 57 * 62 * 67 * 72 * 77 * 82 * 87 * 92 * 94 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 3 * 95 * 96 * 99 * 104 * 109 * 114 * 119 * 124 * 129 * 134 * 139 * 141 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 4 * 142 * 143 * 146 * 151 * 156 * 161 * 166 * 171 * 176 * 181 * 186 * 188 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 5 * 189 * 190 * 193 * 198 * 203 * 208 * 213 * 218 * 223 * 228 * 233 * 235 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 6 * 236 * 237 * 240 * 245 * 250 * 255 * 260 * 265 * 270 * 275 * 280 * 282 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 7 * 283 * 284 * 287 * 292 * 297 * 302 * 307 * 312 * 317 * 322 * 327 * 329 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 8 * 330 * 331 * 334 * 339 * 344 * 349 * 354 * 359 * 364 * 369 * 374 * 376 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 9 * 377 * 378 * 381 * 386 * 391 * 396 * 401 * 406 * 411 * 416 * 421 * 423 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 10 * 424 * 425 * 428 * 433 * 438 * 443 * 448 * 453 * 458 * 463 * 468 * 470 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 11 * 471 * 472 * 475 * 480 * 485 * 490 * 495 * 500 * 505 * 510 * 515 * 517 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 12 * 518 * 519 * 522 * 527 * 532 * 537 * 542 * 547 * 552 * 557 * 562 * 564 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 13 * 565 * 566 * 569 * 574 * 579 * 584 * 589 * 594 * 599 * 604 * 609 * 611 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 14 * 612 * 613 * 616 * 621 * 626 * 631 * 636 * 641 * 646 * 651 * 656 * 658 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 15 * 659 * 660 * 663 * 668 * 673 * 678 * 683 * 688 * 693 * 698 * 703 * 705 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 16 * 706 * 707 * 710 * 715 * 720 * 725 * 730 * 735 * 740 * 745 * 750 * 752 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 17 * 753 * 754 * 757 * 762 * 767 * 772 * 777 * 782 * 787 * 792 * 797 * 799 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 18 * 800 * 801 * 804 * 809 * 814 * 819 * 824 * 829 * 834 * 839 * 844 * 846 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 19 * 847 * 848 * 851 * 856 * 861 * 866 * 871 * 876 * 881 * 886 * 891 * 893 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 20 * 894 * 895 * 898 * 903 * 908 * 913 * 918 * 923 * 928 * 933 * 938 * 940 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 21 * 941 * 942 * 945 * 950 * 955 * 960 * 965 * 970 * 975 * 980 * 985 * 987 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 22 * 988 * 989 * 992 * 997 * 1002 * 1007 * 1012 * 1017 * 1022 * 1027 * 1032 * 1034 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 23 * 1035 * 1036 * 1039 * 1044 * 1049 * 1054 * 1059 * 1064 * 1069 * 1074 * 1079 * 1081 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 24 * 1082 * 1083 * 1086 * 1091 * 1096 * 1101 * 1106 * 1111 * 1116 * 1121 * 1126 * 1128 5

94444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N4444448

Figure 10. Cadastre 5: Typical numbering scheme for NAD 27 Official Protraction

Diagrams 47 cadastre blocks wide in the Alaska OCS Region.

The format for Cadastre 5 OPD's is:

! Dimensions of OPD's: 1Ex2E between latitudes 23EN and 48EN and 1Ex3E

poleward of 48EN.

! Number of columns of blocks: varies from 44 to 47 columns of 4800-by-4800

meter blocks depending upon latitude.

! Number of rows of blocks: 23 (or as necessary 24) rows of 4800-by-4800

meter blocks.

! Area of full cadastre grid blocks: 2304 hectares.

! Starting OPD block number: Block number 1 in column 1, row 1 (usually).

! Block numbering scheme: See Figures 9 & 10.
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As currently implemented, none of the aforementioned cadastres is totally adequate for

use throughout the entire OCS offshore of the conterminous U.S. and Alaska. Although

Cadastre 5 comes close to meeting MMS-wide needs, even it requires modification. Its

main format weaknesses are:

! OPD block configuration varies from 44 up to 47 columns of blocks.

! OPD's were not developed/planned for use in a "worst case scenario." In

order to be applicable MMS-wide (used anywhere on the OCS without

modification or corruption), the cadastre and OPD format needed to be

developed for use at the equator.

! As the MMS develops/updates its computerized databases, the need for a

standardized cadastre has increased.

9.2. NAD 83 OPD Format Considerations

To develop an OPD format that can be used anywhere on the OCS, the following

factors were considered:

1. At the equator:

! One degree of latitude . 111,321 meters.

! A 6E wide UTM zone . 667,926 meters.

! The number of 4800-by-4800 meter blocks per row (or columns of

blocks) in a UTM zone = 140.

! The number of 1Ex2E OPD's across a UTM zone = 3.

! The minimum number of 4800-by-4800 meter blocks per row (or the

number of columns of blocks) on an OPD = 47.

2. Between the equator and 1EN/S:

! One degree of longitude . 110,567.3 meters.

! The number of rows of 4800-by-4800 meter blocks on an OPD = 23 or

24. (MMS OPD's do not necessarily terminate the cadastre on

standard latitude/longitude graticule increments. The cadastre

terminates on a full row of blocks close to the OPD latitudinal limits. To

completely cover the area between the equator and one degree north

(or south) requires slightly more than 23 rows of blocks. Therefore,

depending on the final NAD 83 OPD parameters, 24 rows may be
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PART II –Technical Aspects of Implementation

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Reformatted for the Internet: January 8, 1999

necessary.)

3. Lines of longitude converge towards the poles:

! The distance between lines of longitude approximates a cosine

function. For example, at 60EN/S, the distance between lines of

longitude is approximately 1/2 of equatorial distance for the same pair

of lines. (The cosine of 60E is .5; but since the earth is not a perfect

sphere, at 60EN/S, the distance between a pair of meridians is

approximately half the distance between the same pair of meridians at

the equator.)

! At 48EN/S the convergence of the lines of longitude has become

significant enough to warrant changing the size of the OPD's to 1Ex3E.

9.3. Industry NAD 83 OPD Recommendations

Through a Federal Register notice, the MMS requested comments on the Agency's draft

NAD 83 Implementation Plan. In relation to OPD's and the proposed NAD 83 offshore

cadastre one company operating on the OCS made two recommendations which have

the potential of minimizing the confusion/mixing of NAD 27 and NAD 83 datumdependent data:

! NAD 83 OPD's use 50 blocks per row rather than 47. They felt this would not

create any new problems, but would facilitate the manual use of OPD's. (See

Part II, Appendix A, section 9.4.1. concerning OPD's actually needing to be 48

blocks wide.)

! NAD 83 OPD's should begin with a four digit number (e.g., 2001) in the block

in the northwest corner instead of beginning with the number 1. They felt the

use of a numbering scheme not previously used on OPD's would eliminate, or

at least reduce, the possibility of confusing NAD 83 cadastre blocks with NAD

27 cadastre blocks. (See Part II, Appendix A, section 9.4.1. for a discussion of

why a different block numbering scheme was adopted.)

Further discussion of these two proposals with industry, the coastal States, and within

MMS found that although the concept of a new numbering scheme and cadastre was

not wholeheartedly endorsed, it was not rejected.

9.4. NAD 83 OPD Format

After evaluating the five NAD 27 offshore cadastres and receiving input from the public,

and MMS offices, the MSS developed an NAD 83 OPD and cadastre format that can be

used worldwide, without modification:
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Reformatted for the Internet: January 8, 1999

! Dimensions of OPD's: 1Ex2E between the equator and 48EN/S. (Three OPD's

are needed to cover 1E of latitude across a UTM zone. The actual western

and eastern limits of each of the three OPD's, from west to east, is: (1) the

UTM zone western boundary and X=404,000; (2) X=404,000 and X=596,000;

and (3) X=596,000 and the UTM eastern zone boundary.) 

1Ex3E between 48EN/S and the limit of the UTM grid system at

80EN/S. (Two OPD's are needed to cover 1E of latitude across a

UTM zone. The actual western and eastern limits of each of these

OPD's, from west to east, is: (1) the UTM zone western boundary

and X=500,000; and (2) X=500,000 and the UTM eastern zone

boundary.) 

If OPD's would ever be required poleward of 80EN/S, the metric Universal

Polar Stereographic (UPS) Projection/Grid would be used.

! Number of columns of blocks: 50 columns of 4800-by-4800 meter blocks. 

(See Part II, Appendix A, section 9.4.1.)

! Number of rows of blocks: 23 (or as necessary 24) rows of 4800-by-4800

meter blocks.

! Area of full cadastre grid blocks: 2304 hectares.

! Starting OPD block number: Block 6001 in column 1, row 1 (northwest corner

of the OPD). (See Part II, Appendix A, section 9.4.1.) Note: Due to meridian

convergence, on OPD's adjoining a western UTM zone boundary, even if the

full cadastre grid is depicted, Block 6001 may not be; it and others may lie

entirely west of the UTM zone boundary.

! Block numbering scheme: See Figure 11. (See Part II, Appendix A, section

9.4.1.)

9.4.1. Block Numbering Scheme Rationale. First, between the equator and 48EN/S, a

UTM zone is three OPD's wide. Half of the cadastre blocks should lie west of the

central meridian and half should lie east ("mirror images"). This necessitates the center

of the three OPD's containing an even number of 4800-by-4800 meter blocks per row. 

Therefore, at the equator a minimum of 48 blocks per row becomes the required

minimum, rather than the mathematically computed minimum of 47. Further increasing

the number of blocks per row to 50 does not adversely affect database storage

requirements, and appears to facilitate use of OPD's since the block numbering scheme

is more readily apparent.

Second, NAD 83 block and boundary coordinates and areal measurements will be

metric. For portrayal on OPD's, SOBD's, SOCBD's, etc. coordinates will be computed

to three (3) significant decimal digits and areal measurements to six (6) significant
 a

 If there were to be a NAD 83 Block 818, OPD NH 16-04 (Mobile), the differences would be even more

pronounced in that the coordinates would be in meters and the areal measurements in hectares.

 b

 No increased accuracy is implied between computational systems. Increased significant decimal digits are used

to facilitate the numerous coordinate conversions and datum transformations necessary to implement the metric NAD

83.

 c

 An explanatory note to users concerning the interpretation of block numbers is found on all California LM's. On

CAL Map No. 6C the note reads: "The identification of the blocks is based on the numerical sequence N (North)

starting at the Y origin, and the numerical sequence W (West) starting at the central meridian. Example: Block 10N39W is depicted and referred to as 1039."

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PART II –Technical Aspects of Implementation

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decimal digits. The following NAD 27 comparison for block 818, OPD NH 16-04

(Mobile), illustrates the differences between computations performed using an IBM

mainframe computer and the B&B, TIMS platforma

:

Intersection 1 X=1 203 840.00' Y=10 949 032.28' IBM

X=1 203 840.000' Y=10 949 032.284' B&B, TIMSb

NW Block Corner X=1 188 000.00' Y=10 961 280.00' IBM

X=1 188 000.000' Y=10 961 280.000' B&B, TIMS

State Area "A" 4947.03 Acres IBM

4947.030898 Acres B&B, TIMS

With these differences, a datum conscious user familiar with the NAD 27 and NAD 83

cadastres and their portrayal on OPD's and LM's should not confuse NAD 27

coordinates and areal measurements with NAD 83 coordinates and areal

measurements, even during the transition period prior to full NAD 83 implementation.

It must be noted that even when working with just one datum (e.g., NAD 27), one

cannot cite just a block number without also citing the appropriate OPD or LM. For

example, Block 737 is portrayed on 41 of the 66 NAD 27 OPD's and LM's in the Pacific

OCS Region. Unless one knows the specific OPD or LM, this block could be located

near the shore or near the EEZ. If one knew that the block was on CAL Map No. 6C, it

would immediately be recognized that the block number should be read as "7N-37W."c

Datum and cadastre education/awareness is the best method for ensuring that NAD 27

and NAD 83 data are not mixed.

Third, the occasional OPD/SOBD user, or a user unfamiliar with the MMS OCS

cadastres, may have problems recognizing datum-referenced data well beyond the

transition period to NAD 83. To reduce the potential for mixing NAD 27 and NAD 83

data, the block numbering scheme could be further modified. With the exception of the

LM's in the Pacific OCS Region, block numbering schemes for the NAD 27 cadastres

used numbers smaller than 2000. By using 2001, for example, as the first block on an

OPD, the chance of confusing a NAD 27 block with a NAD 83 block is reduced even

further. In the Pacific OCS Region, the use of 2001 as the initial block number on NAD

83 OPD's would duplicate cadastre block numbers in only a small portion of that OCS
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Reformatted for the Internet: January 8, 1999

Region. Theoretically, because of the unique interpretation of the Pacific OCS Region's

LM block numbers there should be no confusion with any duplicated block numbers on

NAD 83 OPD's.

Finally, to fully minimize confusing NAD 27 and NAD 83 cadastre blocks/data, and to

have a standardized block numbering scheme throughout the entire OCS, NAD 83

cadastre block numbers should be unique, not duplicate any NAD 27 cadastre block

numbers. Block 55N-90W (5590) on CAL Map No. 6A is the largest block number

appearing on any NAD 27 OPD or LM. To avoid duplicating any NAD 27 cadastre block

numbers, on NAD 83 OPD's the most logical starting block number after 2001 is 6001

as illustrated in Figure 11.

64444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L444444L4444447

5Column * 1 * 2 * 3 * 4 * 5 666 10 666 15 666 20 666 25 666 30 666 35 666 40 666 45 666 50 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 Row 1 * 6001 * 6002 * 6003 * 6004 * 6005 * 6010 * 6015 * 6020 * 6025 * 6030 * 6035 * 6040 * 6045 * 6050 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 2 * 6051 * 6052 * 6053 * 6054 * 6055 * 6060 * 6065 * 6070 * 6075 * 6080 * 6085 * 6090 * 6095 * 6100 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 3 * 6101 * 6102 * 6103 * 6104 * 6105 * 6110 * 6115 * 6120 * 6125 * 6130 * 6135 * 6140 * 6145 * 6150 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 4 * 6151 * 6152 * 6153 * 6154 * 6155 * 6160 * 6165 * 6170 * 6175 * 6180 * 6185 * 6190 * 6195 * 6200 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 5 * 6201 * 6202 * 6203 * 6204 * 6205 * 6210 * 6215 * 6220 * 6225 * 6230 * 6235 * 6240 * 6245 * 6250 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 6 * 6251 * 6252 * 6253 * 6254 * 6255 * 6260 * 6265 * 6270 * 6275 * 6280 * 6285 * 6290 * 6295 * 6300 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 7 * 6301 * 6302 * 6303 * 6304 * 6305 * 6310 * 6315 * 6320 * 6325 * 6330 * 6335 * 6340 * 6345 * 6350 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 8 * 6351 * 6352 * 6353 * 6354 * 6355 * 6360 * 6365 * 6370 * 6375 * 6380 * 6385 * 6390 * 6395 * 6400 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 9 * 6401 * 6402 * 6403 * 6404 * 6405 * 6410 * 6415 * 6420 * 6425 * 6430 * 6435 * 6440 * 6445 * 6450 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 10 * 6451 * 6452 * 6453 * 6454 * 6455 * 6460 * 6465 * 6470 * 6475 * 6480 * 6485 * 6490 * 6495 * 6500 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 11 * 6501 * 6502 * 6503 * 6504 * 6505 * 6510 * 6515 * 6520 * 6525 * 6530 * 6535 * 6540 * 6545 * 6550 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 12 * 6551 * 6552 * 6553 * 6554 * 6555 * 6560 * 6565 * 6570 * 6575 * 6580 * 6585 * 6590 * 6595 * 6600 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 13 * 6601 * 6602 * 6603 * 6604 * 6605 * 6610 * 6615 * 6620 * 6625 * 6630 * 6635 * 6640 * 6645 * 6650 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 14 * 6651 * 6652 * 6653 * 6654 * 6655 * 6660 * 6665 * 6670 * 6675 * 6680 * 6685 * 6690 * 6695 * 6700 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 15 * 6701 * 6702 * 6703 * 6704 * 6705 * 6710 * 6715 * 6720 * 6725 * 6730 * 6735 * 6740 * 6745 * 6750 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 16 * 6751 * 6752 * 6753 * 6754 * 6755 * 6760 * 6765 * 6770 * 6775 * 6780 * 6785 * 6790 * 6795 * 6800 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 17 * 6801 * 6802 * 6803 * 6804 * 6805 * 6810 * 6815 * 6820 * 6825 * 6830 * 6835 * 6840 * 6845 * 6850 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 18 * 6851 * 6852 * 6853 * 6854 * 6855 * 6860 * 6865 * 6870 * 6875 * 6880 * 6885 * 6890 * 6895 * 6900 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 19 * 6901 * 6902 * 6903 * 6904 * 6905 * 6910 * 6915 * 6920 * 6925 * 6930 * 6935 * 6940 * 6945 * 6950 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 20 * 6951 * 6952 * 6953 * 6954 * 6955 * 6960 * 6965 * 6970 * 6975 * 6980 * 6985 * 6990 * 6995 * 7000 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 21 * 7001 * 7002 * 7003 * 7004 * 7005 * 7010 * 7015 * 7020 * 7025 * 7030 * 7035 * 7040 * 7045 * 7050 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 22 * 7051 * 7052 * 7053 * 7054 * 7055 * 7060 * 7065 * 7070 * 7075 * 7080 * 7085 * 7090 * 7095 * 7100 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 23 * 7101 * 7102 * 7103 * 7104 * 7105 * 7110 * 7115 * 7120 * 7125 * 7130 * 7135 * 7140 * 7145 * 7150 5

K)))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))3))))))M

5 24 * 7151 * 7152 * 7153 * 7154 * 7155 * 7160 * 7165 * 7170 * 7175 * 7180 * 7185 * 7190 * 7195 * 7200 5

94444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N444444N4444448

Figure 11. NAD 83 OPD numbering scheme.
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10. APPENDIX B--NON-MATHEMATICALLY DEFINABLE

CURVES RESULTING FROM DATUM TRANSFORMATIONS

NAD 27/83 coordinate transformations are non-linear, with the amount of "coordinate

shift" varying with positional location on the earth. Technically, non-mathematically

definable curves result from the transformation of both straight lines and arcs

transformed from NAD 27 to NAD 83, as illustrated by the transformations in Part II,

Appendix B, section 10.2.

Example: On Figure 4, Block 78, LA Map 9A encompasses an area of 14,758

feet (north-south) by 10,450.07 feet (east-west). On NAD 27 a straight line

connects block corners D and E. In the transformation process, the two block

corners do not shift by the same magnitude. NADCON output shows that corner

D has a total shift magnitude of 27.220 meters while corner E has a total shift

magnitude of 27.149 meters, a difference of .071 meters. Breaking the line into

smaller segments (of approximately 2,500 feet for this illustration (points D1-D4))

before transforming results in a better definition of the line, and show that it is

now a complex curve rather than a straight line. Transformation of the northsouth line between block corners E and H produces similar results. The same is

true for arc n-o. All transformations result in complex curves.

The best definition of a transformed line or arc would be achieved by breaking the line

or arc into smaller segments, and the smaller the segments, the better the resulting line

or arc definition after transformation. Three question arise, however. First, into how

many segments should a line or arc be broken? Second, what distance interval should

be used for line and arc segments? Third, for arcs, what radius should be used?

This situation is somewhat akin to the Bureau of Land Management (BLM)/MMS

decision to use a scale factor of "1" for NAD 27 boundary and areal measurement

computations on the UTM grid system. Technically, a scale factor of "1" is applicable

only in specific portions of a UTM zone. However, to simplify the computational process

and to ensure that industry, coastal States, and others could replicate MMS (and

previous BLM) computations, it was decided to use this scale factor throughout a UTM

zone.

To simplify the transformation process, especially for NAD 27 leaseholds, and to ensure

that industry, coastal States, and others can replicate MMS computations, MMS will

consider:

! Straight lines on and within NAD 27 cadastre blocks and boundaries to be

straight lines on NAD 83.

! Geodesic lines on and within NAD 27 cadastre blocks and on boundaries to

be geodesic lines on NAD 83.

! Rhumb lines within NAD 27 cadastre blocks and on boundaries to be rhumb
 a

 Points reference Figure 4. Points D1-D4 are generated points lying between block corners D and E. Points E1-

E5 are generated points lying between block corners E and H. Points n1-n4 are generated points lying between arc

intersections n and o.

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PART II –Technical Aspects of Implementation

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Reformatted for the Internet: January 8, 1999

lines on NAD 83.

! Arcs within NAD 27 cadastre blocks and on boundaries to be arcs of the

same radius on NAD 83.

As with using of a scale factor of "1" for UTM grid system computations, slight

discrepancies in the second or third decimal place can be found by not using some sort

of complex curve definitions. This would not appear to be a problem for two reasons. 

First, the lease instrument, Form MMS-2005 ("Oil and Gas Lease of Submerged Lands

Under the Outer Continental Shelf Lands Act"), does not indicate the type of acres or

hectares being leased (i.e., surface, bottom, grid, etc.). Second, Form MMS-2005,

Section 2, indicates that the areal measurements for the acres or hectares being leased

are approximate.

10.1. Conversion of SPCS Coordinates to Geodetic Coordinates, South Pass

Area, South Addition, LA Map 9A, Block 78, Lambert Projection, Louisiana South

Zone

 NAD 27 SPCS NAD 27 SPCS NAD 27 NAD 27

POINTa EASTING NORTHING LATITUDE LONGITUDE

 C 2605477.93000 61307.90000 28 49 17.45358 89 26 33.98015

 D 2605477.93000 52634.00000 28 47 51.59934 89 26 35.58826

 D1 2605928.00000 52634.00000 28 47 51.52582 89 26 30.53126

 D2 2608428.00000 52634.00000 28 47 51.11648 89 26 02.44119

 D3 2610928.00000 52634.00000 28 47 50.70545 89 25 34.35118

 D4 2613428.00000 52634.00000 28 47 50.29273 89 25 06.26124

 E 2615928.00000 52634.00000 28 47 49.87833 89 24 38.17136

 E1 2615928.00000 54892.00000 28 48 12.22786 89 24 37.74558

 E2 2615928.00000 57392.00000 28 48 36.97273 89 24 37.27412

 E3 2615928.00000 59892.00000 28 49 01.71763 89 24 36.80259

 E4 2615928.00000 62392.00000 28 49 26.46256 89 24 36.33099

 E5 2615928.00000 64892.00000 28 49 51.20753 89 24 35.85934

 H 2615928.00000 67392.00000 28 50 15.95253 89 24 35.38761

 K 2605477.93000 67392.00000 28 50 17.67424 89 26 32.85173

 n 2605477.93000 55164.48000 28 48 16.64598 89 26 35.11920

 n1 2605928.00000 55121.37000 28 48 16.14576 89 26 30.06984

 n2 2608428.00000 54983.84000 28 48 14.37512 89 26 02.00349

 n3 2610928.00000 55018.01000 28 48 14.30227 89 25 33.90529

 n4 2613428.00000 55224.34000 28 48 15.93177 89 25 05.77477

 o 2615928.00000 55605.83000 28 48 19.29331 89 24 37.61097
 a

 Points reference Figure 4. Points D1-D4 are generated points lying between block corners D and E. Points E1-

E4 are generated points lying between block corners E and H. Points n1-n4 are generated points lying between arc

intersections n and o.

44

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

10.2. NAD 27 to NAD 83 Latitude and Longitude Transformations Using NADCON

Version 2.00, South Pass Area, South Addition, LA Map 9A, Block 78

 Shift NAD 27 -

 |-----------NAD 27------------| |--------NAD 83 (1986)--------| NAD 83 (1986) (meters)

POINTa LATITUDE LONGITUDE LATITUDE LONGITUDE LAT. LONG. TOTAL

 C 28 49 17.45358 89 26 33.98015 28 49 18.32283 89 26 34.14873 26.761 4.571 27.149

 D 28 47 51.59934 89 26 35.58826 28 47 52.47108 89 26 35.75573 26.838 4.542 27.220

 D1 28 47 51.52582 89 26 30.53126 28 47 52.39747 89 26 30.69867 26.835 4.540 27.217

 D2 28 47 51.11648 89 26 02.44119 28 47 51.98762 89 26 02.60827 26.820 4.531 27.200

 D3 28 47 50.70545 89 25 34.35118 28 47 51.57609 89 25 34.51793 26.804 4.522 27.183

 D4 28 47 50.29273 89 25 06.26124 28 47 51.16286 89 25 06.42766 26.788 4.513 27.166

 E 28 47 49.87833 89 24 38.17136 28 47 50.74795 89 24 38.33745 26.773 4.504 27.149

 E1 28 48 12.22786 89 24 37.74558 28 48 13.09680 89 24 37.91202 26.752 4.513 27.130

 E2 28 48 36.97273 89 24 37.27412 28 48 37.84091 89 24 37.44094 26.729 4.523 27.109

 E3 28 49 01.71763 89 24 36.80259 28 49 02.58506 89 24 36.96979 26.705 4.533 27.087

 E4 28 49 26.46256 89 24 36.33099 28 49 27.32923 89 24 36.49857 26.682 4.543 27.066

 E5 28 49 51.20753 89 24 35.85934 28 49 52.07345 89 24 36.02730 26.659 4.554 27.045

 H 28 50 15.95253 89 24 35.38761 28 50 16.81769 89 24 35.55596 26.636 4.564 27.024

 K 28 50 17.67424 89 26 32.85173 28 50 18.54174 89 26 33.02110 26.708 4.591 27.099

 n 28 48 16.64598 89 26 35.11920 28 48 17.51700 89 26 35.28699 26.816 4.550 27.199

 n1 28 48 16.14576 89 26 30.06984 28 48 17.01670 89 26 30.23757 26.813 4.548 27.196

 n2 28 48 14.37512 89 26 02.00349 28 48 15.24558 89 26 02.17089 26.799 4.539 27.180

 n3 28 48 14.30227 89 25 33.90529 28 48 15.17220 89 25 34.07238 26.782 4.531 27.163

 n4 28 48 15.93177 89 25 05.77477 28 48 16.80112 89 25 05.94157 26.765 4.523 27.144

 o 28 48 19.29331 89 24 37.61097 28 48 20.16203 89 24 37.77752 26.745 4.516 27.124
45

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

11. APPENDIX C--North American Datum Conversion NAD 83 (1986) to 

NAD 83 (199x) Using Selected OCS Preliminary Baseline Points for the

States of Florida, Oregon, and Washington in NADCON V2.10

 

 Shift NAD 83 (1986) -

 |--------NAD 83 (1986)--------| |--------NAD 83 (1990)--------| NAD 83 (1990) (meters)

Point Latitude Longitude Latitude Longitude Lat. Long. Total

FL 01 30 16 22.86552 87 33 08.57696 30 16 22.86729 87 33 08.57769 .055 .019 .058

FL 02 30 19 27.17631 87 17 49.05712 30 19 27.16859 87 17 49.05897 -.238 .049 .243

FL 03 30 20 07.75563 87 06 48.25350 30 20 07.74212 87 06 48.25568 -.416 .058 .420

FL 04 30 23 46.53870 86 37 46.01714 30 23 46.52044 86 37 46.01453 -.562 -.070 .567

FL 05 30 22 58.53360 86 27 03.64765 30 22 58.51666 86 27 03.64405 -.522 -.096 .530

FL 06 30 20 08.55347 86 11 45.71170 30 20 08.53939 86 11 45.70390 -.433 -.208 .481

FL 07 30 15 03.85516 85 57 06.71000 30 15 03.84304 85 57 06.70053 -.373 -.253 .451

FL 08 30 05 32.39663 85 41 16.43569 30 05 32.38480 85 41 16.42452 -.364 -.299 .471

FL 09 29 59 07.62504 85 31 39.23293 29 59 07.61298 85 31 39.21918 -.371 -.369 .523

FL 10 29 51 36.38371 85 24 42.34829 29 51 36.37240 85 24 42.33297 -.348 -.411 .539

FL 11 29 40 57.67303 85 18 46.23987 29 40 57.66238 85 18 46.22368 -.328 -.435 .545

FL 12 29 37 53.16842 85 06 12.37306 29 37 53.15865 85 06 12.35838 -.301 -.395 .497

FL 13 29 40 17.77657 84 49 53.08910 29 40 17.76743 84 49 53.07772 -.281 -.306 .416

FL 14 29 47 18.47020 84 37 27.17104 29 47 18.46134 84 37 27.16248 -.273 -.230 .357

FL 15 29 53 49.85909 84 23 32.41499 29 53 49.85073 84 23 32.40813 -.257 -.184 .316

FL 16 30 05 07.99560 84 14 12.61406 30 05 07.98748 84 14 12.60824 -.250 -.156 .295

FL 17 30 02 05.27575 83 55 34.04252 30 02 05.26760 83 55 34.03774 -.251 -.128 .282

FL 18 29 53 54.05507 83 39 39.83801 29 53 54.04562 83 39 39.83158 -.291 -.173 .338

FL 19 29 41 51.76616 83 29 23.09125 29 41 51.75469 83 29 23.08219 -.353 -.244 .429

FL 20 29 28 44.62026 83 20 06.65509 29 28 44.61026 83 20 06.64398 -.308 -.299 .430

FL 21 29 19 43.11082 83 10 44.17998 29 19 43.10326 83 10 44.16781 -.233 -.328 .402

FL 22 29 08 53.47072 83 04 38.83440 29 08 53.46483 83 04 38.82257 -.181 -.320 .368

FL 23 29 08 51.96904 82 48 33.01510 29 08 51.96467 82 48 33.00618 -.135 -.241 .276

FL 24 28 52 14.53397 82 43 43.76925 28 52 14.52943 82 43 43.76289 -.140 -.172 .222

FL 25 28 35 29.02372 82 39 41.84857 28 35 29.01958 82 39 41.84184 -.128 -.183 .223

FL 26 28 16 56.84938 82 44 24.68435 28 16 56.84528 82 44 24.67645 -.126 -.215 .250

FL 27 28 03 38.34263 82 49 48.25147 28 03 38.33534 82 49 48.24075 -.225 -.293 .369

FL 28 27 48 34.49967 82 48 53.47049 27 48 34.49295 82 48 53.45790 -.207 -.345 .402

FL 29 27 39 48.31638 82 44 51.06227 27 39 48.31141 82 44 51.04928 -.153 -.356 .387

FL 30 27 31 28.81920 82 44 12.16581 27 31 28.81582 82 44 12.15279 -.104 -.357 .372

FL 31 27 26 30.44570 82 41 28.47944 27 26 30.44314 82 41 28.46666 -.079 -.351 .360

FL 32 27 21 54.83079 82 37 32.72510 27 21 54.82926 82 37 32.71284 -.047 -.337 .340

FL 33 27 17 51.78224 82 34 1.30616 27 17 51.78194 82 34 01.29458 -.009 -.319 .319

FL 34 27 14 54.89891 82 32 12.60112 27 14 54.89959 82 32 12.59011 .021 -.303 .304

FL 35 27 11 57.01621 82 30 24.18141 27 11 57.01690 82 30 24.17044 .021 -.302 .303

FL 36 27 06 20.84408 82 27 45.40970 27 06 20.84442 82 27 45.39861 .010 -.305 .306

FL 37 26 53 54.61317 82 20 41.05928 26 53 54.61280 82 20 41.04616 -.012 -.362 .362

FL 38 26 44 41.29932 82 15 52.24148 26 44 41.29836 82 15 52.22662 -.030 -.411 .412

FL 39 26 35 37.31569 82 13 27.15508 26 35 37.31578 82 13 27.14039 .003 -.406 .406

FL 40 26 27 19.38162 82 08 59.91760 26 27 19.38238 82 08 59.90352 .023 -.390 .391

FL 41 26 27 00.83267 81 57 02.68810 26 27 00.83384 81 57 02.67445 .036 -.378 .380

FL 42 26 19 48.21453 81 50 45.24694 26 19 48.21576 81 50 45.23379 .038 -.365 .367

FL 43 26 07 51.94283 81 48 22.86580 26 07 51.94469 81 48 22.85290 .057 -.358 .363

FL 44 25 58 37.71117 81 44 50.61019 25 58 37.71433 81 44 50.59720 .097 -.361 .374

FL 45 25 52 20.26860 81 42 00.53390 25 52 20.27273 81 42 00.52097 .127 -.360 .382

FL 46 25 49 57.49948 81 30 42.18931 25 49 57.50515 81 30 42.17637 .175 -.360 .400

FL 47 25 45 02.05985 81 22 57.22254 25 45 02.06589 81 22 57.21184 .186 -.298 .351 

OR 01 41 59 36.92189 124 13 56.53843 41 59 36.92958 124 13 56.53416 .237 -.098 .257

OR 02 42 08 16.70419 124 21 48.36595 42 08 16.71828 124 21 48.36001 .435 -.136 .456

OR 03 42 18 02.20443 124 25 00.09229 42 18 02.22421 124 25 00.08248 .610 -.225 .650

OR 04 42 21 18.30298 124 25 35.29142 42 21 18.32384 124 25 35.27898 .644 -.285 .704

OR 05 42 32 59.19448 124 23 48.37308 42 32 59.21724 124 23 48.35052 .702 -.515 .871

OR 06 42 42 03.49363 124 28 46.77796 42 42 03.51733 124 28 46.74767 .731 -.689 1.005

OR 07 42 54 17.48973 124 30 34.19965 42 54 17.51071 124 30 34.15709 .647 -.965 1.162

OR 08 43 04 51.49076 124 26 20.51304 43 04 51.50646 124 26 20.46528 .484 -1.080 1.184

OR 09 43 10 25.19306 124 24 24.71763 43 10 25.20555 124 24 24.66922 .385 -1.093 1.159

OR 10 43 20 37.49898 124 22 54.22773 43 20 37.50631 124 22 54.17738 .226 -1.134 1.156

OR 11 43 24 26.80295 124 18 21.32138 43 24 26.80754 124 18 21.27263 .142 -1.097 1.106

OR 12 43 26 06.10441 124 17 22.12109 43 26 06.10796 124 17 22.07254 .110 -1.092 1.097

OR 13 43 31 39.30975 124 14 49.42040 43 31 39.31025 124 14 49.37220 .016 -1.082 1.082

OR 14 43 40 15.21899 124 13 04.12029 43 40 15.21668 124 13 04.07201 -.071 -1.082 1.084

OR 15 43 49 04.62669 124 10 09.32148 43 49 04.62171 124 10 09.27252 -.154 -1.094 1.105

OR 16 43 56 56.23410 124 08 46.63067 43 56 56.22763 124 08 46.57711 -.200 -1.194 1.211
46

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

 Shift NAD 83 (1986) -

 |--------NAD 83 (1986)--------| |--------NAD 83 (1991)---------| NAD 83 (1991) (meters)

Point Latitude Longitude Latitude Longitude Lat. Long. Total

OR 17 44 04 03.13640 124 07 50.33303 44 04 03.12598 124 07 50.27800 -.322 -1.225 1.266

OR 18 44 17 17.33272 124 06 59.83166 44 17 17.31150 124 06 59.77913 -.655 -1.165 1.336

OR 19 44 22 45.32976 124 07 18.13416 44 22 45.30528 124 07 18.08386 -.756 -1.114 1.346

OR 20 44 30 06.02646 124 05 38.23301 44 30 05.99672 124 05 38.18718 -.918 -1.012 1.367

OR 21 44 36 43.92181 124 04 21.62524 44 36 43.88960 124 04 21.58512 -.994 -.885 1.331

OR 22 44 46 23.71167 124 04 32.71852 44 46 23.67654 124 04 32.68555 -1.085 -.725 1.304

OR 23 44 54 28.09773 124 01 52.31167 44 54 28.05916 124 01 52.28655 -1.191 -.551 1.312

OR 24 44 59 31.48785 124 00 57.00817 44 59 31.44720 124 00 56.98747 -1.255 -.453 1.334

OR 25 45 07 58.87887 123 58 25.21594 45 07 58.84252 123 58 25.20362 -1.122 -.269 1.154

OR 26 45 14 03.27108 123 58 27.02336 45 14 03.23746 123 58 27.01654 -1.038 -.149 1.049

OR 27 45 25 13.96960 123 57 46.05938 45 25 13.93771 123 57 46.06147 -.985 .046 .986

OR 28 45 37 28.77720 123 56 44.68211 45 37 28.74785 123 56 44.69276 -.906 .231 .935

OR 29 45 42 29.58254 123 56 25.98763 45 42 29.55444 123 56 26.00150 -.867 .300 .918

OR 30 45 58 00.48624 123 58 21.70260 45 58 00.45943 123 58 21.72770 -.828 .540 .989

OR 31 46 11 21.57049 123 59 31.03149 46 11 21.55773 123 59 31.06339 -.394 .684 .789

OR 32 46 18 04.45899 124 04 40.85841 46 18 04.45165 124 04 40.88869 -.227 .648 .686

OR 33 46 19 37.15889 124 04 11.16165 46 19 37.15246 124 04 11.19069 -.199 .621 .652

WA 01 46 13 58.16316 124 03 27.44596 46 13 58.15316 124 03 27.47873 -.309 .702 .767

WA 02 46 18 04.55905 124 04 40.65843 46 18 04.55171 124 04 40.68871 -.227 .648 .686

WA 03 46 21 45.55802 124 03 39.16625 46 21 45.55281 124 03 39.19352 -.161 .583 .605

WA 04 46 26 20.35603 124 03 27.97807 46 26 20.35325 124 03 28.00137 -.086 .497 .505

WA 05 46 33 20.95085 124 03 49.29435 46 33 20.95103 124 03 49.31248 .006 .386 .386

WA 06 46 39 07.64510 124 04 36.00551 46 39 07.64714 124 04 36.02020 .063 .312 .319

WA 07 46 46 46.83544 124 06 00.11814 46 46 46.83996 124 06 00.12794 .140 .208 .250

WA 08 46 56 20.71703 124 10 39.82774 46 56 20.72475 124 10 39.83034 .238 .055 .245

WA 09 46 58 51.41358 124 10 22.12854 46 58 51.42201 124 10 22.12926 .260 .015 .261

WA 10 47 00 53.31159 124 10 14.92971 47 00 53.32041 124 10 14.92920 .272 -.011 .273

WA 11 47 04 23.40943 124 10 28.03361 47 04 23.41858 124 10 28.03160 .283 -.042 .286

WA 12 47 11 10.30470 124 12 04.04353 47 11 10.31473 124 12 04.03849 .310 -.106 .328

WA 13 47 26 57.28917 124 24 19.88469 47 26 57.29960 124 24 19.86884 .322 -.332 .463

WA 14 47 35 26.38774 124 22 14.49726 47 35 26.39717 124 22 14.48383 .291 -.281 .404

WA 15 47 40 47.77843 124 29 21.21918 47 40 47.78647 124 29 21.20331 .248 -.331 .414

WA 16 47 49 16.66963 124 33 26.74759 47 49 16.67519 124 33 26.73317 .172 -.300 .346

WA 17 47 54 21.95878 124 39 17.17654 47 54 21.96178 124 39 17.16325 .093 -.276 .291

WA 18 48 09 13.32374 124 45 28.35662 48 09 13.32414 124 45 28.35005 .012 -.136 .136

WA 19 48 24 28.22071 124 44 32.08615 48 24 28.22103 124 44 32.08386 .010 -.047 .048
47

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

12. APPENDIX D--ACRONYMS & ABBREVIATIONS

AWP - Annual Work Plan

B&B, TIMS - The Block and Boundary component of TIMS; See OB2MIS; See TIMS

BLM - (U.S. Department of the Interior,) Bureau of Land Management

 

CONUS - The conterminous United States

DOI - Department of the Interior

DOS - Department of State

EEZ - Exclusive Economic Zone

FGCS - Federal Geodetic Control Subcommittee

FGDC - Federal Geographic Data Committee

FIPS - Federal Information Processing Standards

FR - Federal Register

FY - Fiscal Year

GIS Geographic Information System

GPS - Global Positioning System

GRS 80 - Geodetic Reference System of 1980

HARN - High Accuracy Reference Network (formerly HPGN)

HPGN - High Precision GPS Network (former name of HARN)

IGDC - Interior Geographic Data Committee

INTERMAR - Office of International Activities and Marine Minerals

LM - Leasing Map

MMS - (U.S. Department of the Interior,) Minerals Management Service

MMS/USGS Agreement - April 5, 1991, MMS/Geological Survey (USGS) Agreement
48

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

MSS - MMS, OPDC, Mapping & Survey Staff, formerly the Mapping & Survey Group

(MSG)

NAD 27 - North American Datum of 1927

NAD 83 - North American Datum of 1983

NADCON - North American Datum Conversion transformation software

NGS - (U.S. Department of Commerce, National Oceanic and Atmospheric

Administration, National Ocean Service,) National Geodetic Survey

OB2MIS - Offshore Block, Boundary, and MAP/OPD Information

System; See B&B, TIMS

OCS - Outer Continental Shelf

OCSIS - Outer Continental Shelf Information System; See TIMS(O)

OMB - Office of Management and Budget

OPD - Official Protraction Diagram

OPDC - Office of Program Development and Coordination

OSC - Offshore Systems Center

Part I - "Project Plan for Implementing NAD 83 in the Minerals Management Service,

Part I: Responsibilities and Timeframes"

PLUD - Plot Unit Diagram

RMMC - Rocky Mountain Mapping Center

SOBD - Supplemental Official OCS Block Diagram (also referred to as a "Split Block")

SOCBD - Supplemental Official Composite Block Diagram

SOLD - Supplemental Official Lease Diagram

SPCS - State Plane Coordinate System

SSB - State Seaward Boundary

TAG - Technical Advisory Group
49

PART II –Technical Aspects of Implementation

Originally Released: May 3, 1993

Reformatted for the Internet: January 8, 1999

TBD - To Be Determined

TIMS - Technical Information Management System

TIMS(O) - An all-inclusive reference to the several TIMS components into which OCSIS

is evolving; See OCSIS

U.S. - United States

USGS - (U.S. Department of the Interior,) Geological Survey

UPS - Universal Polar Stereographic

UTM - Universal Transverse Mercator

WGS 84 - World Geodetic System of 1984