HYPACK 2012a Geoid Model and what Datum
Posted by Christian Shaw, Last modified by
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on 29 December 2016 01:00 PM

HYPACK has many predefined Geoid Models in HYPACK Geodesy. I want to talk about the HYPACK 2012a US Geoid Model that we have. 

This model is a gravity based model that is provided by the NGS and NOAA that is an accurate measurement of the earths surface. This allows the RTK GPS reciever to feed HYPACK and given this model compute an elevation of either land or water surface. 

What datum is the US 2012a Geoid. NAVD88. When GPS.dll is offset to the water the tide in the Data Display in SURVEY in the NAVD88 vertical datum. If you would like to compute to another datum you will either have to put in an Orthometric height correction (used for small areas) , construct a KTD file (for large areas. TIN can make this under Export --> XYZ) or use the Vdatum. 

The reason I am writting this is because here in the U.S. with the 2012a Geoid NAVD is the starting point. If you want to go to another datum then you will need to know this separation value and input into HYPACK geodesy from KTD, OHC or Vdatum.