Does WGS84 LatLon coordinates and EGM96 LatLon coordinates are the same?

Is difference for [Lat;Lon;Ele] is in elevation only?

If I have, for example, a [Lat;Lon] point in WGS84, I can take elevation from NASADEM_HGT.001 dataset (which is in EGM96) without any conversion of Lat\Lon and this will be accurate elevation for this point in EGM96. By adding calculated undulation for [Lat;Lon], I can find WGS84 Elevation.

Am I correct ?

How can I 'proof' that to myself? Any docs?


If you inspect the CRS in pyproj for EGM96 it appears to be a Vertical CRS only.

>>> from pyproj import CRS
>>> CRS("EGM96")
<Vertical CRS: EPSG:5773>
Name: EGM96 height
Axis Info [vertical]:
- H[up]: Gravity-related height (metre)
Area of Use:
- name: World
- bounds: (-180.0, -90.0, 180.0, 90.0)
Datum: EGM96 geoid
- Ellipsoid: undefined
- Prime Meridian: undefined

Based on the NGA docs: https://earth-info.nga.mil/GandG/wgs84/gravitymod/egm96/intpthel.html

Geoid heights can be used to convert between orthometric heights (approximately mean sea level) and ellipsoid heights according to the formula:
h   =   H   +   N
h = WGS 84 Ellipsoid height
H = Orthometric height
N = EGM96 Geoid height

Note that EGM96 applies only to the WGS 84 reference ellipsoid.

From this, it appears that EGM96 a geoid model that can be applied to WGS84.

Also related: How does a Spatial Reference System like WGS84 have an elipsoid and a geoid?

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