Guidelines

NOAA Technical Memorandum NOS NGS-58 [pdf]
Guidelines for Establishing GPS-derived Ellipsoidal Heights (Standards: 2 cm and 5 cm) Version 4.3

NOAA Technical Memorandum NOS NGS-59 [pdf]
Guidelines for Establishing GPS-derived Orthometric Heights (Standards: 2 cm and 5 cm) are available. These guidelines address the establishment and densification of vertical control networks through the use of GPS surveys and valid NAVD 88 orthometric control.

Bench Mark Reset Procedures [pdf]
The NGS Bench Mark Reset Guidelines provide the necessary information to preserve elevation data for a soon-to-be disturbed or soon-to-be destroyed bench mark. Bench marks provide a continuous record of elevation changes, as well as vertical control for many local surveyors, and their preservation is vital. It is imperative that elevation information be transferred or referenced from the original bench mark prior to its being disturbed or destroyed. The support and cooperation of local surveyors and engineers in this endeavor is not only important, but essential to the preservation of bench marks.

Information Sheets

• NGS Datasheet - "Height Modernization Survey Station" [example]
• NGS Datasheets may be retrieved by Height Mod station data type

Posters

• Prepare...Utilize...Height Modernization [pdf] [jpg]
  
• The importance of accurate elevations [pdf] [jpg] [ppt]
  
• Height Modernization - State by State (2005) [ppt]

Articles/Reports

• Height Modernization Study - Report to Congress - June 1998
  
• Height Modernization Provides Safer Transportation National Ocean Service News Feature
  
• A Report on NGS and CSRC, 2002 -- A Town Hall Meeting on Height Modernization,
  Riverside CA, April 4, 2002 [pdf format]
  
• Results of the General Adjustment of the North American Vertical Datum of 1988
  NAVD 88 Federal Register Notice:
  
• Affirmation of Vertical Datum for Surveying and Mapping Activities (June 23, 1993)
  
• Baltimore County, Maryland, NAVD 88 GPS-derived Orthometric Height Project
  
• Establishment Of International Great Lakes Datum (1985)
  by The Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data (Dec 1985)
  
• Establishing Vertical Control Using GPS Satellite Surveys
  
• Geodetic Program Needs of Louisiana and Wisconsin - Report to Congress
  
• Height Modernization Activities flyer
  
• NGS/CALTRANS San Diego GPS-Derived Orthometric Height Cooperative Project
  
• GPS Satellite Surveys and Vertical Control Dave Zilkoski, Journal Of Surveying, VOL. 115 NO. 2, May 1989 [ISSN 0733-9453]
  
• Minimum Steps Required When Estimating GPS-Derived Orthometric Heights
  
• From The Ground Up -- a need for height modernization By Mark E. Meade, POB magazine article, March 2004
• Rates of Vertical Displacement at Benchmarks in the Lower Mississippi Valley and the Northern Gulf Coast -- NOAA Technical Report 50, July 2004

Other Articles of Interest

Mark Cheves, Editor of Professional Surveyor Magazine, talks about Increased Accuracy for GPS Heights in the May/June 1996 issue. This article describes research being carried out at NGS to improve the accuracy of geometric heights determined by GPS.

Dave Zilkoski and Don D'Onofrio discuss the Geodetic Phase of NOS's San Francisco Bay Demonstration Project in a paper prepared for presentation to the American Congress on Surveying and Mapping.

Report on the Joint Coast Survey and National Geodetic Survey Centimeter-Level Positioning of a Marine Vessel Project: The U. S. Coast Guard Buoy Tender Test
Louisiana Sinking to Earth's Core - article in The Advocate ONLINE internet publication, February 18, 2002.

Meeting Notes

• Height Modernization Coordination Group Meeting Notes
  
  2005
  January 11 [pdf]
  February 8 [pdf]

Presentations