# Presentation: 683655

## Height Modernization Forum

- Program Overview
- Anchorage, Alaska
- October 5, 2005
- 		Juliana Blackwell
- 		Height Modernization Program Manager
- 		National Geodetic Survey, NOAA**	****  **

## National Geodetic Survey Priorities Cooperation, Collaboration, Coordination

## Background

- Heights
- Needs and Benefits
- Outreach

- Height Modernization

## Height Modernization is ...

## Height Modernization Objective

**Notes:**
Just like building a house, having a strong, well-planned, standardized foundation for surveying, engineering, GIS, etc., geospatial referencing is critical.
Otherwise, what you “build” on top of it won’t hold up or “fit in.”    

## Height Modernization Objective

** **** **

** **

**NSRS**

**NAVD 88**

**GEODETIC CONTROL**

**National Vertical Datum accessed through**
** ****the NSRS Infrastructure that is:**

**Reliable**

**Cost-effective**

**Accurate**

**Standardized**

**Legally Established**

**Notes:**
Information about where an object or feature is or where an event takes place is known as spatial data.  We use spatial data all the time. 
National Spatial Reference System – a consistent coordinate system that defines latitude, longitude, height, scale, gravity, and orientation throughout the United States and how these values change with time.  Comprised of an accurate, up-to-date national shoreline, a network of CORS (Continuously Operating Reference Stations), a network of ground monuments, and a set of accurate models that describe processes affecting spatial measurements.
Spatial data is crucial to economy, resource management, the environment and emergency response.
Transportation - Surface waters - Boundaries - Geodetic control - Elevation - Aerial imagery 
National Spatial Data Infrastructure – Formalized effort of the federal, state and local government, private groups to develop and use a consistent, reliable means to share spatial data.
Geodetic control is NGS’ responsibility.

## Background

**Notes:**
History -- California first state to draw attention to deficit in NAVD 88.  Hard to pin down movement in CA.  A lot of the state did not get adjusted in NAVD 88.  Especially southern California because the leveling was so old.  Grassroots effort to begin Height Mod.
In 1997, Height Modernization was mentioned in our appropriation language for the first time. No money allocated, but NGS encouraged to investigate the concept of Height Mod. 
In 1998, $1.0 M was added to NGS budget to perform Height Modernization Study.
In 1999,  Height Modernization not mentioned.
In 2000, $500K added to NGS budget to perform Height Modernization planning.
In 2001, $2.25 M added to NGS budget to perform Height Modernization in North Carolina, to support the California Spatial Reference Center (CSRC), and to support NGS related Height Modernization activities.
Also In June 2001, NGS was directed to report to Congress about the Height Mod needs of LA and WI. LA had similar issues with data not being adjusted into NAVD 88.  (Due to subsidence). WI had a very active Height Mod program by the WisDOT. Very active in GIS. Problems with obsolete geodetic control & rapid land loss thru subsidence and erosion.
FY 2001: CA 1.0, NC 1.0, NGS 0.25	 (FY2001-FY2005 in millions of $)
FY 2002: CA 1.0, NC 1.0, LA 1.0, WI 0.5
FY 2003: CA 1.0, NC 1.0, LA 0.5, WI 0.5, MS 0.5
FY 2004: CA 1.0, NC 1.0, LA 0.5, WI 3.0, MS 0.5, AL 2.0, SC 0.5, WA 0.5 
FY 2005: CA 0.5, NC 1.0, LA 0.5, WI 3.0, MS 0.6, AL 2.0, WA 0.5, KY 0.5, TX 0.75

## Slide 8

**Notes:**
History 
California first state to draw attention to deficit in NAVD 88.  Hard to pin down movement in CA.  A lot of the state did not get adjusted in NAVD 88.  Especially southern California because the leveling was so old.  Grassroots effort to begin Height Modernization.
In 1997, Height Modernization was mentioned in our appropriation language for the first time. No money allocated, but NGS encouraged to investigate the concept of height modernization.
In 1998, $1.0 M was added to NGS budget to perform Height Modernization Study.

## Height Modernization Background

**Notes:**
In 1999,  Height Modernization not mentioned.
In 2000, $500K added to NGS budget to perform Height Modernization planning
In 2001, $2.25 M added to NGS budget to perform Height Modernization in North Carolina, to support the California Spatial Reference Center (CSRC), and to support NGS related Height Modernization activities.
Also In June 2001, NGS was directed to report to Congress about the Height Mod needs of Louisiana and Wisconsin.  Louisiana had similar issues with data not being adjusted into NAVD 88.  (Due to subsidence).  Wisconsin had a very active Height Mod program by the DOT.  Very active in GIS.  Problems with obsolete geodetic control and rapid land loss thru subsidence and erosion.

## Height Modernization 

| Fiscal Year | Appropriations  | States |
| --- | --- | --- |
| FY 2001 | 2.25 M | CA, NC |
| FY 2002 | 3.75 M |   CA, NC, LA, WI |
| FY 2003 | 3.75 M | CA, NC, LA, WI, MS |
| FY 2004 | 9.0 M | CA, NC, LA, WI, MS, 
AL, WA, SC |
| FY 2005 | 9.6 M | CA, NC, LA, WI, MS, 
AL, WA, TX, KY |

- Height Modernization Appropriations
**(FY01-FY05)**

**Notes:**
FY 2001: CA 1.0M, NC 1.0M, NGS 0.25M
FY 2002: CA 1.0M, NC 1.0M, LA 1.0M, WI 0.5M
FY 2003: CA 1.0M, NC 1.0M, LA 0.5M, WI 0.5M, MS 0.5M
FY 2004: CA 1.0M, NC 1.0M, LA 0.5M, WI 3.0M, MS 0.5M, AL 2.0M, SC 0.5M, WA 0.5M 
FY 2005: CA 0.5M, NC 1.0M, LA 0.5M, WI 3.0M, MS 0.6M, AL 2.0M, WA 0.5M, KY 0.5M,     TX 0.75M

## FY05 Height Modernization Funding

**($ in thousands)**

| CA | 500 | California Spatial Reference Center at Scripps Institution of Oceanography  |
| --- | --- | --- |
| LA | 497 | Louisiana State University -- Louisiana Spatial Reference Center |
| WA | 500 | Washington State Department of Natural Resources for the Spatial Reference Center of Washington |
| NC | 1,000 | North Carolina Department of Environmental and Natural Resources (also to North Carolina A&T State University in past years, but no information at this time for FY05) |
| WI | 3,000 | Wisconsin Department of Transportation  |
| AL | 2,000 | Alabama Department of Revenue |
| MS | 600 | University of Southern Mississippi  |
| *TX | 750 | Texas A&M University, Corpus Christi  |
| *KY | 500 | Morehead State University |
| NGS | 250 | Height Modernization Regional Expansion – NGS Implementation |

*** ****New states **

**Notes:**
FY05 Overview of Height Modernization Funding – appropriated amounts and recipients.
$9.6M total for FY05

## Height Modernization Status

**Notes:**
NGS’ Height Modernization map --  states funded for Height Mod are shown in purple and states that have demonstrated a strong interest and outreach program are in light blue. 
Once the web page is fully constructed, you will be able to click on a state and find out about projects, meetings, forums, who to contact, etc...
FY 2005: CA 0.5M, NC 1.0M, LA 0.5M, WI 3.0M, MS 0.6M, AL 2.0M, WA 0.5M, KY 0.5M, TX 0.75M
FY 2004: CA 1.0M, NC 1.0M, LA 0.5M, WI 3.0M, MS 0.5M, AL 2.0M, WA 0.5M, SC 0.5M

## Heights

- Height Modernization

## The Goal of Height Modernization

- Compute accurate orthometric (“sea level”) heights using GPS technology

**Notes:**
Up to now, orthometric heights have been achieved using leveling observations.
Leveling is too expensive and time consuming.

Is this easy?  No.  GPS gives us ellipsoid heights.
How do we turn these into orthometric heights.

## 1) What types of heights are involved?
		•  Orthometric heights
		•  Ellipsoid heights
		•  Geoid heights

2) How are these heights defined and related?

3) How accurately can these heights be determined?

- 		•  Orthometric heights
- 		•  Ellipsoid heights
- 		•  Geoid heights
- 2) How are these heights defined and related?
- 3) How accurately can these heights be determined?

- How to achieve accurate GPS heights

**Notes:**
Need to understand the three different heights to fully understand GPS derived orthometric heights.

Heights & Datums  - traditionally orthometric heights meant above sea level.  

You need to be aware of the limitations of each height system to understand what you get when using GPS to determine heights.

## Conventional Leveling

**BM**
**100’**

- ROD 1

- INSTR

**H**

**H = Orthometric Height**  **(NAVD 88)**

**H** ** = ****h**** - ****N**

- TOPOGRAPHIC SURFACE

**h = Ellipsoidal Height (NAD 83)**

**N = Geoid Height (GEOID 03)**

- Ellipsoid, Geoid, and Orthometric Heights

- A

- B

**Notes:**
Orthometric height is the height on the surface above the geoid.  But we can’t measure from the geoid so we use leveling. The NAVD88 is defined from the control point, B, in Quebec.  Because the ortho ht at A is computed from leveling observations, where error is modeled or estimated, it probably isn’t right at the geoid, right at “sea level”.

Our vertical datum is defined.  We need a geoid that we can use that is relative to the vertical datum. 

Note that in this picture the geoid is shown above the ellipsoid.  In the continental United States, the geoid is actually below the ellipsoid, so the value of the geoid height is negative.

## What is the GEOID?

- “The *equipotential surface* of the Earth’s gravity field which best fits, in the least squares sense, mean sea level.”*
- Can’t see the surface or measure it directly.
- Can be modeled from gravity data.
-    *Definition from the Geodetic Glossary, September 1986

**Notes:**
What does equipotential surface mean – If we could see or measure the geoid, this could be our vertical datum.  But we are dependant on leveling observations on the surface to create our datum.

## In Search of the Geoid...

- Courtesy of Natural Resources Canada  www.geod.nrcan.gc.ca/index_e/geodesy_e/geoid03_e.html

## What’s Left?

- Leveling-Derived Orthometric Heights
- Modeled Geoid Heights
- GPS-Derived Ellipsoid Heights

**Notes:**
We know how to get 
  - Accurate orthometric heights at benchmarks by leveling – this is expensive and time consuming!  But these are still the best heights you can get.

We now are able to develop a hybrid geoid model from a gravimetric geoid model with
 - Accurate ellipsoid heights
 - More benchmarks with GPS measurements – the better the NAVD88, the better the geoid model

How do we get improved ellipsoid heights?
Better field procedures
Accurate ellipsoid heights at control stations

## GPS Error Sources

- Orbit and clock error
- Broadcast v.s. Predicted Precise v.s. Post-processed
- Clock error corrections
- Atmospheric Effects
-  Ionosphere, Troposphere
- Multipath
- Height of phase center above mark

**Notes:**
You can choose which orbit to use – Post-processed is most accurate, but predicted is now also very accurate.
Clock error is negligible.
Ionosphere and Troposphere are modeled now, and can be corrected for.  Corrections are generally in the software.

## GPS Heights Guidelines   

**Available “On-Line” at**
**the NGS Web Site:**
**www.ngs.noaa.gov**

## Height Modernization Project

**Notes:**
Sample Monument Spacing:

HARN 		50 km	(75 km max for 2 cm)
Primary GPS		20-25 km	(40 km max for 2 cm)
Secondary GPS	12-15 km	(15 km max for 2 cm)
Local GPS		6-8 km	(10 km max for 2 cm)
In addition to the HARN and primary control, ALL secondary and local base stations will have GPS-derived “orthometric” heights.

## Needs and Benefits 

- Needs and Benefits

- Height Modernization

## Height Modernization 

- Why Height Modernization?

**Notes:**
Determination of the “Real” Rate of Sea Level Rise
Precise Positioning of Dredges and Dredge Materials
Positioning of ships, clearance, draft

## Specific Examples

- Water management
- Measuring subsidence
- Evacuation routes
- Water levels
- Emergency Management
- FEMA/Flood plain maps
- Flood insurance
- Map Modernization
- Restoration
- Transportation
- Agriculture

## Height Modernization

**Notes:**
Height Modernization – the importance of accurate elevations 
Modern society is becoming increasingly dependent on geographic data that is spatially referenced – horizontally and vertically.  In order to determine accurate floodplains, study the amount and effects of runoff, improve agricultural yields, manage coastal resources, or improve transportation systems we need accurate, easily accessible information on the elevations of terrain, coastal and inland waters, buildings, roads, pipelines, aircraft, ships, etc., as well as how the heights behave over time.
Navigation Control: active maritime shipping and navigation through inland waterways.
Transportation Control: highway, rail, and airway monitoring.
High-yield farming: connecting remote sensing and GIS to the application of fertilizers and pesticides onto farmland. 
Construction: Machine control by GPS.
Emergency Management: locating infrastructure and efficiently moving resources to their destination.
Flood Management: measuring flood zones precisely on a common framework is critical.
Water Management: monitoring of reservoirs, groundwater, etc.
Crustal Motion: studies of the earth’s surface and reactions to motion.

## Benefits from Height Modernization

- Good control improves the administration of the National Flood Insurance Program
- Floodprone building permits and flood insurance rating require accurate building elevations
- Good control produces consistent, accurate results
- Denser control can reduce survey costs
- Height modernization will make GPS survey faster, easier and less expensive

## HEIGHT Modernization Supports MAP Modernization

- HEIGHT Modernization Supports MAP Modernization

- Height Modernization control for floodplain maps and LIDAR surveys
- OPUS for floodplain certificates and LIDAR surveys
- Subsidence rates, maps, and tools for floodplain managers
- Guidelines for use of GPS and LIDAR for floodplain mapping

## Water Management

- Harris-Galveston Subsidence District

**Notes:**
The Harris Galveston Subsidence District has measured subsidence since 1975 with the  use of mechanical Borehole Extensometers (basically a deep set benchmark measured relative to the land surface).  
land surface elevation changes in the Houston area measured by leveling back to 1906 
In the mid-1980's, a third method of measuring land-surface elevation changes was developed with the help of the National Geodetic Survey (NGS), using the Global Positioning System (GPS) to provide site specific locations and elevations. 
- starting in the mid 1990's, began developing the use of GPS Port-A-Measures (PAMs) to provide monthly, weekly, and even daily subsidence measurements.  Small PAM trailers shelter and secure the GPS receivers and provide a platform for solar panels to power the recording equipment.  The trailers are moved periodically from site to site to record data every 30 seconds from a GPS antenna sitting atop a PAM pole (benchmark).  Each PAM pole is permanently set into the ground.  Currently the District operates 7 PAM trailers on a weekly schedule, allowing for 28 PAM sites to be measured on a monthly basis.  The data is downloaded each week and processed against the 3 GPS CORS sites.  The District maintains a MS PowerPoint file, showing the data collected from each PAM site. 

## Transportation

- Establish horizontal and vertical coordinates for design surveys
- 40 – 50% less time
- Less time needed for error analysis between GPS and Leveling derived elevations
- All positions are easily re-established
- Reduced the need for any conventional leveling
- Instant coordinates

- _Wisconsin Department of Transportation and RTK_** **

**Notes:**
 Began in 1998 - Wisconsin Department of Transportation 
 Improve height data (the vertical component of the geodetic network) in WI
 Goal-eliminate inconsistencies between horizontal and vertical control data 
 Supplement control where marks have been destroyed
 Create network that can fully utilize GPS technologies  (cost effective)
Products of HMP:
Conventionally Leveled Bench Marks (BM’s)
FGCS 2nd Order Class 1
Published on North American Vertical Datum of 1988 (NAVD 88)
GPS Stations
Horizontal FGCS B-order and 1st Order and GPS derived Vertical 2-cm positional accuracy
Published on North American Datum of 1983 (1997 adjustment) (NAD 83 (97)) and NAVD 88

## FEMA 

- Flood Insurance Risk Maps
- Determining High Water Marks
- Elevation Certificates
- Dam Safety
- Mitigation

**Notes:**
 Height Modernization improves the “foundation” for the determination of floodplain maps for FEMA’s Map Modernization program.
 Digitizing maps that are based on outdated, inaccurate heights is not worthwhile – ensuring that the heights used for the floodplain and flood insurance rate map are updated and accurate is critical. 
 Areas shown in pink delineate the “New 100 yr floodplain” (with HeightMod) – areas in light blue the previous “FEMA Effective Approximate 100yr floodplain” (old survey control)
Builders, owners and planners in “pink” areas now aware that they are in the 100yr floodplain and will be able to insure their property as needed.  Future building and zoning will done with better knowledge of elevations and flood risks.
 Benefits to FEMA:
 Three dimensional geodetic control network to support map modernization
 Establish bench marks in remote areas (2 centimeters)
 Global Positioning System (GPS) base station network to support collect of elevation (LIDAR and photogrammetry) and imagery
 Compared to traditional leveling, GPS heights can be established at a reduced cost
 Quickly establish bench marks in declared disaster areas to support recovery and mitigation
 Support the development of flood warning systems
 Provide elevation data to support dam breach analysis

Potential Products and Tools for Map Modernization
 Height Modernization control for floodplain maps and LIDAR surveys
 OPUS for floodplain certificates and LIDAR surveys
 Subsidence rates, maps, and tools for floodplain managers
 Guidelines for use of GPS and LIDAR for floodplain mapping

## HEIGHT Modernization Supports MAP Modernization

**HEIGHT** Modernization Supports **MAP** Modernization

- Height Modernization control for floodplain maps and LIDAR surveys
- OPUS for floodplain certificates and LIDAR surveys
- Subsidence rates, maps, and tools for floodplain managers
- Guidelines for use of GPS and LIDAR for floodplain mapping

## California Spatial Reference Center

- Includes a mix of CORS and traditional monuments along transportation corridors
- Implementation dependent on technological developments (wide-area RTK, real-time networks, and wireless communications)
**A complete data set of NAVD88 **
**heights will be computed for the **
**California CORS network.**

**Master Plan for a spatial reference network for height modernization and geodetic control in California**

**Notes:**
The Network 
 50 Km CORS
 7 Km Corridors

The System
 4 Dimensional
 Geodetic Models
 Height Datum
 Data Distribution
 Education & Outreach
 Information Management

Researching procedures leads to development of new specs.

## North Carolina Height Modernization

**Notes:**
NC Ht Mod Began in FY 2001 
Green areas – survey work by contractor
Red – survey work by NCGS
The North Carolina Geodetic Survey began working with FEMA and other agencies to quickly update the outdated FIRMs after Hurricane Floyd in Sept 1999. On September 15, 2000, one year after Hurricane Floyd, North Carolina became the first Cooperating Technical State (CTS). As a CTS, North Carolina assumed primary ownership and responsibility for the production and maintenance of new digital FIRMs. This developed into the North Carolina Floodplain Mapping Program, which uses height modernization to gather elevation data. New elevation data help evaluate and improve the accuracy of the floodplain maps. With North Carolina’s vulnerability to hurricanes and flooding, communities and property owners need to have accurate, up-to-date information about flood risks. 

## Louisiana Spatial Reference Center

**Notes:**
View of Plaquemines Parish at Empire and River
Y 195 RESET
Evacuation Route Surveys 

## Measuring Heights Along Evacuation Routes   

## RTK Profiling of Highway

**Notes:**
Test new technologies which can be used for height mod surveys

## Louisiana Evacuation Route Survey

- Vertical Time Dependent Positioning (VTDP)

**-26.9 ( ****-0.7**** )**

**-25.2  ( ****-7.0***** )**

**-23.1 ( ****1.1**** )**

**-25.6 ( ****0.5**** )**

**-23.3 ( ****-7.4**** *)**

**-9.6 ( ****-0.3**** )**

**-24.2 ( ****-0.8**** )**

***Outlier**

**Black - Amount of Subsidence Since Last Leveling (1982  yrs) – cm**
**Red - Difference between Predicted Height and GPS-derived Orthometric Height**

**Notes:**
Use historical leveling data and new GPS data to estimate rate of subsidence.  Develop tools to predict future change.

## Wisconsin Height Modernization Plan

**Notes:**
 Began in 1998 - Wisconsin Department of Transportation 
 Improve height data (the vertical component of the geodetic network) in WI
 Goal-eliminate inconsistencies between horizontal and vertical control data 
 Supplement control where marks have been destroyed
 Create network that can fully utilize GPS technologies  (cost effective)
Products of HMP:
Conventionally Leveled Bench Marks (BM’s)
FGCS 2nd Order Class 1
Published on North American Vertical Datum of 1988 (NAVD 88)
GPS Stations
Horizontal FGCS B-order and 1st Order and GPS derived Vertical 2-cm positional accuracy
Published on North American Datum of 1983 (1997 adjustment) (NAD 83 (97)) and NAVD 88
Proposed Timeline (April 2004): 
          Phase 5            Phase 6	Phase 7	    Phase 8
2004  Level/GPS        Monument	Recon	    ---
2005  Adjust/Publish   Level/GPS	Monument	    Recon
2006   ---	              Adjust/Publish	Level/GPS	    Monument
2007   ---	              ---		Adjust/Publish   Level/GPS 
2008   ---                     ---		---	    Adjust/Publish
Winnebago County updated 10’ contour maps to 2’ contour maps
2,400 structures removed from the floodplain – save on unnecessary flood insurance, property values increase
1,300 structures added to the floodplain – can purchase protection
Total savings to these owners $14 million!

## Spatial Reference Center of Washington

**Technical Considerations and Objectives**

-  **Ensure a high-accuracy geodetic reference network in WA **(GPS, monuments, CORS, VRS networks, geodetic models).
** ****Ensure that survey data provided to NGS for inclusion into National Spatial Reference System (NSRS) database.  **
** ****Promote the Washington Spatial Reference System.**
** ****Ensure availability of time-dependent geospatial information.**
** ****Promote the development of specifications and guidelines for GPS surveys**
** ****Serve as an educational source for users and potential users.**
** ****Foster cooperation and partnerships**

**Notes:**
Ensure that a high-accuracy, horizontal and vertical geodetic reference network is maintained in WA State -- based on GPS and related technologies and consist of in-ground monuments, CORS, Virtual Reference Station Networks, and geodetic models as necessary to meet the spatial positioning needs within Washington for surveying, Height Modernization, engineering, Earth Science research (e.g., crustal motion/earthquake studies), geographic information systems (GIS), geomatics engineering, resource management, disaster preparedness and recovery, Homeland Defense concerns, and other activities dependent upon reliable spatial referencing.
Ensure that applicable GPS data and other observations by the Center are processed, adjusted, and provided to NGS, with appropriate electronic data files and related information, for inclusion into the NSRS database.  Such efforts shall be in accordance with accepted NGS procedures and Washington State Surveying codes and procedures.
Promote the Washington Spatial Reference System (as part of NSRS) as Washington’s official spatial reference system.
Ensure that time-dependent geodetic coordinates, velocities, GPS data, and supplemental station information (historical coordinates, seismic data, etc.) are distributed to agencies, research entities, and other public and private organizations involved in spatial referencing.
Promote the development of specifications and guidelines for GPS surveys, not otherwise provided at the national level.  Develop an Implementation Plan for a modern Washington Geodetic Control Network that will meet the goals of the National Height Mod Program in Washington – this being the initial component of a statewide referencing network.
Serve as an educational source for users and potential users on (a) spatial referencing issues, (b) availability and application of the center’s data, products, and other information, and (c) services available from the Center.
Foster cooperation and partnerships among agencies, research entities, and organizations involved in spatial referencing issues

## Texas Height Modernization 

- Texas Height Modernization

- Establish Texas Spatial Reference Center at Texas A&M-Corpus Christi
- Integrate Height Modernization with Texas Coastal Ocean Observation Network (TCOON)
- Conduct research and measurements for improvement of geoid model in Texas/Gulf Coast Region
- Co-locate GPS CORS at Water Level gauges
- Measure/monitor subsidence in Harris Galveston Coastal Subsidence District

- TCOON

## Alabama Height Modernization

- Alabama Department of Revenue
-   - countywide GIS mapping projects
- Alabama Department of Transportation
-   - oversees surveying tasks
- Goals
-  Primary Base Network 40 to 50 km grid
-  Leveling to Primary Base Marks
-  CORS

| Phase I | Phase II-V |
| --- | --- |
| Install 4-6 CORS in priority urban areas; evaluate | Add 4 to 6 CORS per year 
 |
| Provide real-time, single baseline positioning via internet | Provide network corrections once 100 km spacing is reached |

**Notes:**
Plan of Work (2005-2006) Alabama Height Modernization Program (ALHMP)
The Alabama Department of Revenue (ALDOR) and the Alabama Department of Transportation (ALDOT) in cooperation with NOAA, National Geodetic Survey (NGS) have implemented a Height Modernization Program in Alabama.  ALHMP is a series of surveying activities designed to modernize the vertical component of the National Spatial Reference System (NSRS).  This network will provide the State of Alabama and its citizens with a statewide high precision Global Positioning System (GPS) reference network to support all geo-spatial activities in the state.  
Alabama’s existing network is comprised of First Order and Second Order level lines dating back to the 1930’s, and a network of First Order horizontal control monuments established in the late 1980’s and early 1990’s.  Both of these components have deteriorated dramatically due to increased development and the lack of a central agency to monitor and maintain this network.  It is estimated that as much as fifty percent of the vertical benchmarks have been destroyed or deemed unreliable, and as much as sixty-five percent of the horizontal monuments have been destroyed or are no longer suitable for GPS observations.  In addition, these horizontal monuments do not have an accurate vertical component.  
The Height Modernization efforts will restore the horizontal network and establish elevations on these monuments to support GPS activities. Height Modernization activities also include establishing a Continuously Operating Reference Stations (CORS) network, additional first order level lines, establishing a Local Base Network on a 7 to 10 km spacing, and connecting tide stations to the NAVD 88 to monitor the amount of coastal subsidence and inland upheaval.
The first year of Alabama’s Height Modernization Activities began the work on completion of the High Accuracy Reference Network (HARN) and Primary Base Network.  A voluntary effort has been completed to establish 110 A and B order monuments on a forty kilometer grid.  The first phase of the Height Modernization Project completed the GPS observations on the remaining monuments in February 2005.  
The second year of Alabama’s Height Modernization Activities will continue work on completion of the High Accuracy Reference Network (HARN) and Primary Base Network.  Conventional level runs to establish Second Order, Class I, NAVD88 elevations on each of the A and B order monuments will continue on the Primary Base Points.  Funding will be used in FY05 to continue approximately 580 miles of leveling from existing First or Second Order Benchmarks.  A portion of the leveling funds will be used to establish elevations on Secondary Base Points using leveling to ensure good vertical ties in the Secondary Base Network.  This second year plan will continue work to establish the CORS network concentrating on areas of need.  These areas will be the major urban areas, stations at tidal benchmarks along the coast and one for the Geomatics Program at Troy University. 
ALDOR will continue the countywide GIS mapping projects that support the Height Modernization Program. These mapping activities will continue at the county level to support this plan and therefore leverage the available funding for the network and establishing elevations for those monuments identified in the existing network as useful in the Height Modernization Program. Approximately restoration of the horizontal.
This project will provide land information services for ALDOR and its customers (taxpayers), Alabama state and county agencies, and federal and local government agencies through a portal concept. The Geodetic Framework Layer is the anchor for the accuracy and precision of the entire system. Inclusion of the Height Modernization Program data results is crucial to the establishment of this layer and to the long-term maintenance of the NSRS in Alabama.

## Mississippi Height Modernization

- FY’05 Accomplishments
- University of Southern Mississippi
- Purchased equipment for 11 CORS
- Selected 8 Gulf Coast counties sites for CORS installations
- Developed plan to extend CORS network throughout the State (30 CORS)
- USM Gulf Coast Research Lab installed National Water Level Observation Network (NWLON) station co-located with CORS
- Long-term plan to install two other NWLON stations along the coast
- Contract survey work planned
- Height Modernization survey along Mississippi River (Cairo, IL to the Gulf) completed in cooperation with USACE

## Kentucky Height Modernization

- Morehead State University

- 1st Priority:
**CORS**
- 2nd Priority:
**GPS on BMs**
**Improved**
** ****Geoid Model**

## Outreach

- Height Modernization

## Outreach

- NGS Geodetic Advisor Program
- NGS Workshops
- NGS Monthly Height Modernization Coordination Group Meetings
- Height Modernization Webpage - _**www.ngs.noaa.gov/heightmod/**_

## NGS Web Site

## Height Modernization Web Page

## Guidelines and Procedures

- GPS-derived Orthometric Heights Guidelines
- Digital Leveling Guidelines
- Methods of Determining Orthometric Heights at CORS
- Guidelines for Submitting USGS 3rd Order Leveling Data

## Models and Tools

- Vertical Time-dependent Positioning
- Pocket GPS Manager
- Web-based User-friendly Leveling Processing, Adjustment, and Analysis Software
- VDatum
- Improved Geoid Model

## NGS’ Role and Responsibilities

**Outreach/Technology Transfer --**** **advisors, forums, workshops, conferences, publications, training, outsourcing
**Project Leadership** **--** project planning, specifications, guidelines, CORS management
**Quality Control --** training, assess techniques, survey control, load projects into NGS database
**Research and Development** **--** software development, remote sensing, modeling, investigate GPS techniques, antenna calibrations

## Partnerships

**State Agencies**** –****	**North Carolina Geodetic Survey
- 			South Carolina Geodetic Survey
- 			Wisconsin Department of Transportation
- 			Alabama Department of Revenue
- 			Washington Department of Natural Resources
**Spatial Reference Centers**** –** California, Louisiana, Washington
**Universities**** –** University of Southern Mississippi
- 		 North Carolina A&T State University
- 		 Louisiana State University
- 		 University of California/Scripps
- 		 Texas A&M University-Corpus Christi
-                         Morehead State University

**Notes:**
“Formal” partnerships are listed.
In addition, several other agencies and groups are working with NGS on the Height Modernization effort. 

## Forums, Conferences & Workshops

- Forum and Hawaii Surveying Conference, HI
- Real Time GPS Networks Symposium, Irvine, CA
- ACSM Conference, Las Vegas, NV
- Louisiana Surveyors Conference, Houma, LA
- State Floodplain Mapping Conference, Madison, WI
- Coastal Zone ’05, New Orleans, LA
- Survey and GIS Summit, San Diego, CA
- ESRI International Users Conference, San Diego, CA
- Height Modernization Forum, Huntsville, AL
- GPS Real-Time Networks in the Northwest, Wenatchee, WA
- Height Modernization Workshop, Greensboro, NC
- Height Modernization Workshop, Osage Beach, MO
- Height Modernization Forum, Anchorage, AK
- National Height Modernization Workshop, Silver Spring, MD
- Trimble International User Conference, Las Vegas, NV

**Notes:**
FY04 – 28 events 

## Results

- Eliminates inconsistencies between horizontal and vertical control data
- Supplements control where marks have been destroyed or are deemed unusable
- Utilizes GPS technologies as a cost effective positioning tool

**The Height Modernization Program --**

## The Future

- Continue to investigate opportunities to modify procedures and processes to improve efficiencies.
- Provide outreach training and support to states interested in Height Modernization.
- Continue efforts to maintain and grow the program.
- Research new technology to enhance HMP efforts.

## Point of Contact

**Height Modernization Program Manager**
- 1315 East-West Highway
- Silver Spring, MD  20910
- 301-713-1054
- Juliana.Blackwell@noaa.gov

## Questions?  

- Questions?