Opened 7 years ago

Last modified 5 years ago

#67 new enhancement

Updated pj_ellps.c with non-Earth planetary ellipsoids

Reported by: cirquelar Owned by: warmerdam
Priority: minor Milestone:
Component: Core Version: Development (trunk)
Keywords: ellipsoids Cc:


I updated the file pj_ellps.c to contain the non-Earth planetary ellipsoids (e.g. Mars) with the appropriate semi-major axis (a) and semi-minor axis (b) or reciprocal flattening (rf) parameters (attached).

All values are derived from the latest pertinent report (in 2000) provided by the International Astronomical Union (IAU) Working Group (IAU/IAG WG) on Cartographic Coordinates and Rotational Elements. The reference for the report is "Report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites: 2000," by P. K. Seidelmann, et al., now published in Celestial Mechanics and Dynamical Astronomy, 82, pp. 83-110, 2002. A preprint with the values is available here:

These values match the default ESRI ArcGIS 9.3.1 projection files for geographic coordinate systems for the solar system (C:\Program Files\ArcGIS\Coordinate Systems\Geographic Coordinate Systems\Solar System). I did not update the pj_datums.c file as there are not multiple datums for any of the planetary bodies.

While PROJ.4 can work with non-Earth coordinate systems via specifying the semi-major axis, reciprocal flattening and appropriate projection elements (e.g. latitude of true scale), this addition will standardize the ellipsoid sizes on peer-reviewed values and assist scientists working with this software to conduct planetary research.

Attachments (1)

pj_ellps.c (7.3 KB) - added by cirquelar 7 years ago.

Download all attachments as: .zip

Change History (5)

Changed 7 years ago by cirquelar

comment:1 Changed 7 years ago by cirquelar

  • Priority changed from major to minor

comment:2 Changed 7 years ago by cirquelar

  • Version changed from unspecified to 4.7.0

comment:3 Changed 7 years ago by cirquelar

  • Version changed from 4.7.0 to Development (trunk)

comment:4 Changed 5 years ago by warmerdam

  • Milestone 4.8.0 deleted

This is not release critical for 4.8.0. In general I am not too keen on extending the built in lists of named ellipsoids, datums, etc. Initialization files are (imho) a better solution for such definitions.

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