USA Geoid Models
Posted by James Johnston on 28 January 2019 01:55 PM
MicroSurvey data collection software can make use of NGS .bin "little endian" format Geoid Separation files to correct elevations collected using GPS for geoid separation.
These files can be downloaded from the National Geodetic Survey Geoid page:
NOTE: The NGS website is sometimes down. In order to get the USA Geoid files, we have posted a link to them below, which were the latest files as of Dec-2018
Older Data Collectors
In the past, data collectors came with a smaller memory-storage capacity. Geoid model files could easily fill up the entire data collector's hard drive, or were even too large to transfer to the device.
Because of this we created this utility that makes a subset of the geoid model that is small enough to fit on a data collector's hard drive. Typically you would create a subset based on the location of the project area. Currently, all MicroSurvey data collectors come with an enormous storage-memory capacity therefore making geoid model subsets unnecessary (we now just copy the entire geoid model file onto the data collector) and that is why we now say it is "optional".
If you wish to create a geoid model subset, click on the link below to download the Datum Grid Editor.
NOTE: You must be using FieldGenius 2010 or older, the Datum Grid Editor is not supported in newer versions.
Download Datum Grid Editor - 110 Megabytes
Note: The Datum Grid Editor currently only works on North American geoid models.