GRAV-D Data Products

Available data may include airborne and terrestrial survey information, gravity data, and gravity-based geoids or datums. Open the GRAV-D Data Products Dashboard by selecting the hyperlink or the map below. Once the dashboard opens, select the block of interest in the map or list on the left. The right hand panel will populate with general information and a link that will lead to data available for download.

General Airborne Gravity User Manual

The General User Manual, which describes data distribution, field operation details, post-processing, and how to calculate commonly used gravity values, is available below. User Manuals for each block, which describes specific collection and error details for those data, are included in the zip file when the data is downloaded. Each User Manual specifies which version of the General Manual applies to that data set.

  • Version 2.1: Released on September 19, 2017, this version includes updates to equipment, aircraft, accuracy calculations, and minor details for post-processing and applies to data releases starting in September 2017.
  • Version 2.0: Released on March 28, 2013, this version includes significant updates to field procedures and post-processing and applies to data releases starting in February 2013.
  • Version 1.1: Released on December 5, 2012, this version supersedes v 1.0 of the manual and fixes minor errors in the previous version. Most important is a corrected typo for the GRS-80 first eccentricity squared value reported on page 20 of the document.

Airborne Gravity Data - Map Key

  • Green: Available data and metadata
  • Blue: Data being processed
  • Orange: Data collection underway
  • White: Planned for data collection

GRAV-D Data Products Dashboard

image of the GRAV-D Data Products Dashboard map.  Shows areas where airborne gravity data collection efforts.

Experimental Geoid Products

Starting in 2014, the National Geodetic Survey (NGS) began publishing a series of experimental geoid (xGEOID) models annually. The xGEOID models are continually improved each year and each subsequent model incorporates the new airborne gravity data that are released within the preceding year.

Experimental Geoids