NAP3XD
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United States
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patiam Posted at 5-12 08:12
Your drone data geotag Z vaules are in Height Above Ellispoid (HAE). You need to apply the Geoid height (Ellipsoid-Geoid separation), or whatever the difference is between the ellipsoid and your preferred vertical datum (if it is not orthometric) in Pix4D when you set the output coordinate system (under Advanced>Geoid Height Above the Ellipsoid).
You can get the Geoid Height for your study site from various online calculators (there is a UNAVCO one below). They will let you choose the Geoid model you wish to use (eg. GEOID 12B, GEOID 18, etc.). You may also be able to get the Geoid height for the CORS station which you could use if it is very nearby (the Geoid varies over space so if you want the best accuracy possible, use a Geoid height for the center of your study area. Unfortunately Pix4D only allows you to inpt a singe height. Some software will let you specify a raster file to better capture the Geoid height variability).
Thanks for sharing, been using ODM -> QGIS, any suggestions on a workflow to get prover ELEV heights? |
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