0

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?

1

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
Where,
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?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.