BOREAS Elevation Contours over the NSA and SSA in ARC/Info Generate Format

Summary

This data set was prepared by BORIS staff by reformatting the original data into 
the ARC/INFO Generate format.  The original data were received in SIF at a scale 
of 1:50,000. BORIS staff could not find a format document or commercial software 
for reading SIF; the BOREAS HYD-08 team provided some C source code that could 
read some of the SIF files.  The data cover the BOREAS NSA and SSA.  The original 
data were compiled from information available in the 1970s and 1980s.  The data 
are available in ARC/Info Generate format files.

Note that the files of this data set on the BOREAS CD-ROMs have been compressed 
using the Gzip program.  See section 8.2 for details.

Table of Contents

   *  1 Data Set Overview
   *  2 Investigator(s)
   *  3 Theory of Measurements
   *  4 Equipment
   *  5 Data Acquisition Methods
   *  6 Observations
   *  7 Data Description
   *  8 Data Organization
   *  9 Data Manipulations
   *  10 Errors
   *  11 Notes
   *  12 Application of the Data Set
   *  13 Future Modifications and Plans
   *  14 Software
   *  15 Data Access
   *  16 Output Products and Availability
   *  17 References
   *  18 Glossary of Terms
   *  19 List of Acronyms
   *  20 Document Information

1. Data Set Overview

1.1 Data Set Identification

BOREAS Elevation Contours over the NSA and SSA in ARC/Info Generate Format

1.2 Data Set Introduction

This vector contour data set was prepared by BOReal Ecosystem-Atmosphere Study 
(BOREAS) staff by reformatting the original data into the ARC/INFO Generate 
format.  These data cover portions of the BOREAS Northern Study Area (NSA) and 
Southern Study Area (SSA) and are on a scale of 1:50,000.

1.3 Objective/Purpose

These data are provided as part of the BOREAS Staff Science Geographic 
Information System (GIS) Data Collection Program-which included the collection of 
pertinent map data in both hard-copy and digital form.  The purpose of these data 
is to provide the user with elevation contours of the Modeling Sub-Areas (MSAs).  
These data can be used to create digital Elevation Models (DEMs) ofthe MSAs.  The 
original Standard Interchange Format (SIF) data were reformatted to the ARC/INFO 
Generate format because it was considered difficult for an average user to 
extract the contours from the SIF files.

1.4 Summary of Parameters

The parameters that are in the reformatted data are the elevation of the contour 
(meters above mean sea level) and North American Datum 1983 (NAD83) Universal 
Transverse Mercator (UTM) coordinate pairs (easting and northing) along the 
contour.

1.5 Discussion

Based on information available to BOREAS Information system (BORIS) personnel, 
these data were manually digitized from the National Topographic System (NTS) map 
sheets at a scale of 1:50,000.  The data were given to BOREAS staff in SIF and 
K8A (the meaning of K8A is unknown) formats.  C source code provided by the 
BOREAS HYD-08 team was modified to read the contour data from various files.  The 
input data were understood to be in a standard format, but they were not standard 
in terms of the softwares ability to consistently read all of the data files.

1.6 Related Data Sets

BOREAS HYD-8 Digital Elevation Models in UTM

BOREAS Vector Contours in SIF and K8A formats

2. Investigator(s)

2.1 Investigator(s) Name and Title

David Knapp
BORIS Information System Staff member

2.2 Title of Investigation

BOREAS Staff Science GIS Data Collection Program

2.3 Contact Information

Contact 1
----------
David Knapp
NASA/GSFC
Greenbelt, MD  
(301) 286-1424
(301) 286-0239 (fax)
David.Knapp@gsfc.nasa.gov

Contact 2
----------
Jaime Nickeson
NASA/GSFC
Greenbelt, MD 
(301) 286-3373
(301) 286-0239 (fax)
Jaime.Nickeson@gsfc.nasa.gov


3. Theory of Measurements

These data were not collected with any particular research in mind.

4. Equipment

4.1 Sensor/Instrument Description

Unknown.

4.1.1 Collection Environment

Unknown.

4.1.2 Source/Platform

Unknown.

4.1.3 Source/Platform Mission Objectives

The implied purpose of the NTS 1:50,000-scale map sheets was to provide users 
with needed location and topographic information.

4.1.4 Key Variables

Elevation above mean sea level North Amercan Datum (NAD)83 Universal Transverse 
Mercator (UTM) Coordinate Pairs

4.1.5 Principles of Operation

Unknown.

4.1.6 Sensor/Instrument Measurement Geometry

Unknown.

4.1.7 Manufacturer of Sensor/Instrument

Unknown.

4.2 Calibration


4.2.1 Specifications

Unknown.

4.2.1.1 Tolerance

Unknown.

4.2.2 Frequency of Calibration

Unknown.

4.2.3 Other Calibration Information

None.

5. Data Acquisition Methods

The data were acquired from the National Topographical Data Base and received 
from the Canadian Centre for Remote Sensing (CCRS).  The original data came in 
SIF, digitized from 1:50,000-scale topographic maps.

6. Observations

6.1 Data Notes

None.

6.2 Field Notes

None.

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

The various data files cover parts of the BOREAS NSA-Modeling Sub-Area (MSA) and 
SSA-MSA.

The two areas that are covered by these vector files include an area west of 
Thompson, Manitoba (NSA), and an area north of Prince Albert, Saskatchewan (SSA). 
Each of the following maps covers an area roughly 31.5km x 27.8km.

The following NTS map sheets are covered by the data:

For the NSA:
Number            Name
------        --------------
63 O/10        Wuskwatim Lake
63 O/15        Nelson House
63 O/16        Noble Lake
63 O/09        Ospwagan Lake
63 P/14        Begg Lake
64 A/03        Orr Lake
64 A/04        Strong Lake
64 B/01        Harding Lake
64 B/02        Leftrook Lake

For the SSA:
Number            Name
------        --------------
73 G/09        Halkett Lake
73 G/16        Waskesiu Lake
73 H/09        Torch River     
73 H/10        Bedard Creek
73 H/11        Birchbark Lake
73 H/12        Emma Lake
73 H/13        Bittern Lake
73 H/14        Candle Lake
73 H/15        White Gull Creek
73 H/16        Falling Horse Creek
73 I/01        Scarth River
73 I/02        Summit Lake
73 I/03        Whiteswan Lake
73 I/04        Montreal Lake South
73 J/01        Crean Lake

The area covered by these sheets does not cover all of the area described by the 
following bounding coordinates.  These bounding areas are provided to give a 
general idea of where these map sheets fall.

                  NSA-MSA
            Longitude  Latitude
            ---------  --------
Northwest    98.72W     56.055N
Northeast    98.09W     55.990N
Southeast    98.18W     55.726N
Southwest    98.81W     55.790N
 

                   SSA-MSA
             Longitude  Latitude
             ---------  --------
Northwest    105.18W     54.093N
Northeast    104.42W     54.053N
Southeast    104.48W     53.695N
Southwest    105.23W     53.735N

7.1.2 Spatial Coverage Map

Not available.

7.1.3 Spatial Resolution

The original contour interval of the data is 25 feet (7.62 m).

7.1.4 Projection

The data are in their original UTM projection.  The NSA data are in UTM zone 14, 
and the SSA data are in UTM zone 13.
 
7.1.5 Grid Description

Quantitative estimates were not made of the mean spacing between points along the 
contour lines.  Visual assessment of the data showed the spacing to be 
appropriate for the 1:50,000 scale (i.e., there was no noticeable jaggedness or 
discontinuities along the contours).

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

Information regarding when the original source data were collected is sketchy.  
Most of the maps from which these contours were digitized were made in the 1970s 
or 1980s.

7.2.2 Temporal Coverage Map

Not available.

7.2.3 Temporal Resolution

Although these data were likely compiled from map and aerial photograph vintages 
covering 10 or more years, they are considered to be a single reference data set.

7.3 Data Characteristics

7.3.1 Parameter/Variable

Elevation above mean sea level
NAD83 UTM coordinate pairs along a given elevation contour

7.3.2 Variable Description/Definition

Elevation above mean sea level - The vertical distance between a plane at mean 
sea level and a parallel plane intersecting this point.

NAD83 UTM coordinate pairs along a given elevation contour - The NAD83-based UTM 
easting and northing coordinate pairs that define the geographic locations over 
which the given contour exists.

7.3.3 Unit of Measurement

Elevation above mean sea level - meters
NAD83 UTM coordinate pairs along a given elevation contour - UTM meters

7.3.4 Data Source

Geomatics Canada
Natural Resources Canada
615 Booth St.
Ottawa, Ontario   K1A 0E9   CANADA

7.3.5 Data Range

NSA-MSA
Elevation
(meters)
-----------
Minimum: 206
Maximum: 381
      
SSA-MSA
Elevation
(meters)
------------
Minimum: 335
Maximum: 747


7.4 Sample Data Record

442
 533084.00,  5939891.00
 533079.00,  5939891.00
 533061.00,  5939889.00
 533033.00,  5939897.00
 532950.00,  5939902.00
 532877.00,  5939910.00
 532849.00,  5939918.00
 532784.00,  5939950.00
 532747.00,  5939991.00
 532714.00,  5940015.00
 532539.00,  5940100.00
END

                        
8. Data Organization

8.1 Data Granularity

The smallest amount of data obtainable is the entire set of vector contour files.

8.2 Data Format(s)

8.2.1 Uncompressed Data Files

The vector contour data set consists of a set of 24 files in the following order:

File  1: Data for Map 73 G/09   (400 bytes per record) SSA
File  2: Data for Map 73 G/16   (400 bytes per record)
File  3: Data for Map 73 H/09   (400 bytes per record)
File  4: Data for Map 73 H/10   (400 bytes per record)
File  5: Data for Map 73 H/11   (400 bytes per record)
File  6: Data for Map 73 H/12   (400 bytes per record)
File  7: Data for Map 73 H/13   (400 bytes per record)
File  8: Data for Map 73 H/14   (400 bytes per record)
File  9: Data for Map 73 H/15   (400 bytes per record)
File 10: Data for Map 73 H/16   (400 bytes per record)
File 11: Data for Map 73 I/01   (400 bytes per record)
File 12: Data for Map 73 I/02   (400 bytes per record)
File 13: Data for Map 73 I/03   (400 bytes per record)
File 14: Data for Map 73 I/04   (400 bytes per record)
File 15: Data for Map 73 J/01   (400 bytes per record)

File 16: Data for Map 63 O/09   (400 bytes per record)
File 17: Data for Map 63 O/10   (400 bytes per record)
File 18: Data for Map 63 O/15   (400 bytes per record)
File 19: Data for Map 63 O/16   (400 bytes per record)
File 20: Data for Map 63 P/14   (400 bytes per record)
File 21: Data for Map 64 A/03   (400 bytes per record)
File 22: Data for Map 64 A/04   (400 bytes per record)
File 23: Data for Map 64 B/01   (400 bytes per record)
File 24: Data for Map 64 B/02   (400 bytes per record)

The 24 data files each contain maximum record sizes of 400 bytes.  Each physical 
record on tape consists of 1 to 10 logical records of 40 bytes each.  As noted 
previously, the data in the files are stored in the ARC/INFO Generate format.  
Within each file, the data in the 40-byte logical records are stored as American 
Standard Code for Information Interchange (ASCII) characters.  The records are 
arranged in groups that contain varying numbers of records.  The first record of 
the group contains the value for the elevation above mean sea level.  This is 
followed by the records containing the UTM easting and northing coordinate pairs 
for that elevation contour.  At the end of each contour, a record containing the 
ASCII characters END indicates the end of the contour.  A second record 
containing the ASCII END characters is given at the end of the contour groups 
to indicate the end of the file.  The following listing illustrates this format.

442                         <-------- This is the contours elevation (meters)
 533084.00,  5939891.00     <-------- This is the first of a series of UTM                    
 533079.00,  5939891.00               coordinates (easting, northing) that
 533061.00,  5939889.00               define the contour.
 533033.00,  5939897.00
 532950.00,  5939902.00
 532877.00,  5939910.00
 532849.00,  5939918.00
 532784.00,  5939950.00
 532747.00,  5939991.00
 532714.00,  5940015.00
 532539.00,  5940100.00
END                         <-------- This marks the end of this contour.
465                         <-------- The elevation of the next contour.
 531985.00,  5953858.00
 531985.00,  5953866.00
 531972.00,  5953881.00
 531950.00,  5953891.00
 531899.00,  5953894.00
 531853.00,  5953913.00
 531774.00,  5953915.00
 531744.00,  5953899.00
...
 531734.00,  5953875.00
 531745.00,  5953826.00
 531766.00,  5953808.00
END                      <----- This marks the end of this contour.
END                      <----- This marks the end of the file.

8.2.2 Compressed CD-ROM Files

On the BOREAS CD-ROMs, all the files listed in section 8.2.1 have been 
compressed with the Gzip compression program (file name *.gz).  These data have 
been compressed using gzip version 1.2.4 and the high compression (-9) option 
(Copyright (C) 1992-1993 Jean-loup Gailly).  Gzip (GNU zip) uses the Lempel-Ziv 
algorithm (Welch, 1994) used in the zip and PKZIP programs. The compressed files 
may be uncompressed using gzip (-d option) or gunzip.  Gzip is available from 
many websites (for example, ftp site prep.ai.mit.edu/pub/gnu/gzip-*.*) for a 
variety of operating systems in both executable and source code form.  Versions 
of the decompression software for various systems are included on the CD-ROMs.

9. Data Manipulations

9.1 Formulae

The only data value conversion performed by BORIS staff was to convert the 
elevation measurements in feet in some (not all) of the files to meters.  This 
was done by dividing the elevation values of feet by 3.28 and then rounding the 
result.

9.2 Data Processing Sequence

9.2.1 Processing Steps

BORIS staff processed the original data to the current product by:

1) Attempting to read a file with the provided software.
2) Modifying the C source code and updating the file header to read the specific 
file.
3) Running the program to extract contours from the file and create output files.
4) Writing the output files to tape.
5) Copy the ASCII and compress the binary files for release on CD-ROM.

9.2.2 Processing Changes

None.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

There appeared to be two types of files in the original set.  In many cases, the 
header information in each file had to be modified in order for the modified 
software to extract the contours successfully.

9.3.2 Calculated Variables

See Section 9.1.

9.4 Graphs and Plots

None.

10. Errors

10.1 Sources of Error

One source of error is the digitizing process used to create the contours from 
the map sheets.  It is not known whether the maps were hand digitized or if 
software was used to digitize the contours.  In either case, the error is 
probably negligible.   

10.2 Quality Assessment

10.2.1 Data Validation by Source

Unknown.

10.2.2 Confidence Level/Accuracy Judgment

Unknown.

10.2.3 Measurement Error for Parameters

Unknown.

10.2.4 Additional Quality Assessments

None.

10.2.5 Data Verification by Data Center

After extracting the data into the ARC/INFO Generate files, BORIS staff plotted 
the contour data and visually reviewed the data with the 1:50,000-scale hardcopy 
maps.  No anomalies or errors were detected in this review.

11. Notes

11.1 Limitations of the Data

Because the data have a 25-foot contour interval, variations in the terrain that 
are smaller than 25 feet may not be detectable.  The user should not expect to 
see terrain detail such as small berms or other minor topographic relief.

11.2 Known Problems with the Data

The NSA maps from which these data were derived were found to be in disagreement 
with BOREAS gathered and differentially corrected GPS coordinates by about 150 
meters.  The error did not appear to be systematic.  The SSA maps have a higher 
degree of accuracy (about 45 meters) when compared to GPS.   

11.3 Usage Guidance

If these data are going to be used to create a DEM, the various vector files 
should be edge-matched to create seamless contours that do not have 
discontinuities at the map boundaries.

Before uncompressing the Gzip files on CD-ROM, be sure that you have enough disk 
space to hold the uncompressed data files.  Then use the appropriate 
decompression program provided on the CD-ROM for your specific system.

11.4 Other Relevant Information

None.

12. Application of the Data Set

These data can be used to create a gridded DEM of the area of interest as well as  
for graphical purposes, as an overlay along with other vector layers.
 
13. Future Modifications and Plans

None.

14. Software

C source code from HYD-8 for converting from SIF or K8A format.

14.1 Software Description

The software to read the SIF and K8A was originally produced by an unknown 
source, although it was obtained from HYD-08.  The software reads the input file 
and extracts certain features based on feature codes that are supplied by the 
user.

Gzip (GNU zip) uses the Lempel-Ziv algorithm (Welch, 1994) used in the zip and 
PKZIP commands.

14.2 Software Access

The software is written in C and is operational on UNIX workstations at GSFC. The 
software is available by contacting the ORNL DAAC or BOREAS Staff.

Gzip is available from many websites across the net (for example) ftp site 
prep.ai.mit.edu/pub/gnu/gzip-*.*) for a variety of operating systems in both 
executable and source code form. Versions of the decompression software for 
various systems are included on the CD-ROMs.

15. Data Access

15.1 Contact Information

Primary contact:

Ms. Beth McCowan
BOREAS Data Manager
NASA/GSFC
Greenbelt, MD 
(301) 286-4005
(301) 286-0239 (fax)
beth@ltpmail.gsfc.nasa.gov

15.2 Data Center Identification

See Section 15.1.

15.3 Procedures for Obtaining Data

Users may place data requests by telephone, electronic mail, or fax.

15.4 Data Center Status/Plans

The NSA and SSA elevation contour data are available from the Earth Observing 
System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) 
Distributed Active Archive Center (DAAC).

The BOREAS contact at ORNL is:

ORNL DAAC User Services
Oak Ridge National Laboratory
(865) 241-3952
ornldaac@ornl.gov
ornl@eos.nasa.gov

16. Output Products and Availability

16.1 Tape Products

The vector contour data can be made available on 8-mm, Digital Archive Tape 
(DAT), or 9-track tapes at 6250 or 1600 Bytes Per Inch (BPI).

16.2 Film Products

None.

16.3 Other Products

These data are available on the BOREAS CD-ROM series.

17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

Welch, T.A. 1984, A Technique for High Performance Data Compression, IEEE 
Computer, Vol. 17, No. 6, pp. 8 - 19.

17.2 Journal Articles and Study Reports

Sellers, P., F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. 
Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). 

Sellers, P., F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. 
Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). 

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere 
Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). 

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere 
Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). 

Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. 
Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. 
Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and 
early results from the 1994 field year. Bulletin of the American Meteorological 
Society. 76(9):1549-1577. 

Sellers, P., F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue (in press).


17.3 Archive/DBMS Usage Documentation

None.

18. Glossary of Terms

None.

19. List of Acronyms

ASCII     - American Standard Code for Information Interchange
BOREAS    - Boreal Ecosystem-Atmosphere Study
BORIS     - BOREAS Information System
BPI       - Bytes Per Inch
CCRS      - Canadian Centre for Remote Sensing
CD-ROM    - Compact Disk-Read-Only-Memory
DAAC      - Distributed Active Archive Center
DAT       - Digital Audio Tape
DEM       - Digital Elevation Model
EOS       - Earth Observing System
EOSDIS    - EOS Data and Information System
GIS       - Geographic Information System
GMT       - Greenwich Mean Time
GSFC      - Goddard Space Flight Center
MSA       - Modeling Sub-Area
NAD27     - North American Datum 1927
NAD83     - North American Datum 1983
NASA      - National Aeronautics and Space Administration
NSA       - Northern Study Area
NTS       - National Topographic System
ORNL      - Oak Ridge National Laboratory
PANP      - Prince Albert National Park
SIF       - Standard Interchange Format
SSA       - Southern Study Area
URL       - Uniform Resource Locator
UTM       - Universal Transverse Mercator
WWW       - World Wide Web

20. Document Information

20.1 Document Revision Date(s)

     Written:         09-Jun-1995
     Last Updated:    22-Jan-1998

20.2 Document Review Date(s)

     BORIS Review: 06-Jun-1997
     Science Review: 

20.3 Document ID

20.4 Citation

These data originated as vector data that were provided to BORIS staff through 
CCRS by Geomatics Canada.  The contribution of the data by CCRS and Geomatics 
Canada and processing of the data by BORIS staff are greatly appreciated.

20.5 Document Curator

20.6 Document URL

Keywords
-----------------
Elevation Contours
NSA_SSA_Elev_Contours.doc
04/17/98