GEOID12A Data Download

NOTICE: NGS Update, September 11, 2012

GEOID12A Model Released

The National Geodetic Survey has released the GEOID12A model. Analysis of the underlying control data has been completed and a number of corrections were made to the original data used in making GEOID12. Changes impacted regions in the states of Alabama, Mississippi, Louisiana, Texas, Oklahoma, and Wisconsin. GEOID12A is now available for production and use.

GEOID12A Data Download Description

For working with the GEOID12A model, two computer programs are provided as compiled executables for both PC Win32 (INTG.EXE and XNTG.EXE) and Sun Unix (INTG and XNTG) platforms, along with the source code in a zip file. INTG interpolates geoid heights from data files using user-provided coordinates. XNTG extracts sub-grids from the binary data files, converts back and forth between binary and ASCII data formats, and gives statistics about a data file.

To determine geoid heights with the GEOID12A model, download an INTG executable and at least one data file. You need only to select those data files that cover your region of interest, and the program will recognize which files are present. Select one or more of the data files either by using the graphical or data interfaces.

Download the data files for your particular operating system. The binary formats of the Unix format data files follow the IEEE Std. 754 binary format (big-endian) as they are developed in a Unix environment. Programs INTG, XNTG, INTD and XNTD are all designed to determine the user's platform and will automatically byte swap the data. Data files for use on a Windows platform (little endian) are reformatted accordingly.