Changes between Version 3 and Version 4 of VerticalCS


Ignore:
Timestamp:
02/07/11 10:58:21 (14 years ago)
Author:
warmerdam
Comment:

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  • VerticalCS

    v3 v4  
    4444== Ellipsoidal Heights ==
    4545
    46 One way of describing elevations is relative to an ellipsoid rather than to a more specialized vertical datum.  The 1.0 GeoTIFF specification ( [http://www.remotesensing.org/geotiff/spec/geotiff6.html#6.3.4.1 section 6.3.4.1) listed ellipsoidal VertCS values in the range 5000 to 5033; however, those do not appear to have any corresponding definitions in modern EPSG databases.  I am currently taking the position that it those should therefore be disregarded.
     46One way of describing elevations is relative to an ellipsoid rather than to a more specialized vertical datum.  The 1.0 GeoTIFF specification ( [http://www.remotesensing.org/geotiff/spec/geotiff6.html#6.3.4.1 section 6.3.4.1]) listed ellipsoidal VertCS values in the range 5000 to 5033; however, those do not appear to have any corresponding definitions in modern EPSG databases.  I am currently taking the position that it those should therefore be disregarded.
    4747
    4848Instead I propose that we just treat ellipsoidal heights by not specifying any VerticalCSTypeGeoKey code and letting the ellipsoid be determined from the ProjectedCSTypeGeoKey, !GeographicTypeGeoKey or !GeogEllipsoidGeoKey.   Thus a GeoTIFF defined as follows would be assumed to have ellevations in meters relative to the WGS84 ellipsoid.