Ellipsoidal DEMs in Base Area: ISIS/GDAL Radii Mismatch

[jlaura]

ISIS version(s) affected: ALL

Description

The mola DEM in the ISIS base area (version 0005 as of today) is provided in a simple cylindrical projection, ocentric latitude. Via gdalinfo that DEM reports semi-major and semi-minor axes of 3396190, spherical. The data's PVL label reports an ellipsoidal body.

Effectively, the data are in a spherical projection (#5325) and gdal is forcing a sphere (hopefully). The mismatch here is confusing for users (who might dig this deep?).

Why does this matter? Within ISIS, it probably does not as everything is internally consistent. But, when using the ISIS base area DEMs with the CSM, specifically via the knoten.Surface classes one has to specify the radii, potentially leading to this confusion.

How to reproduce

Possible Solution

If the data are effectively using a spherical body, then the ISIS label and GDAL spatial reference should match. Options seem to be to either update GDAL or re-release the ISIS cubes with updated labels.

Additional context