error reading IDL/ENVI created GeoTIFFs

I have confirmed that the spheroid is lost in a translation to JPEG2000 using the JP2KAK driver. This is unrelated to the warning about a missing null at the end of the ascii parameters. I'll dig into the spheroid issue...

A listgeo of the input file shows:

   Keyed_Information:
      GTModelTypeGeoKey (Short,1): ModelTypeProjected
      GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
      GeographicTypeGeoKey (Short,1): Undefined
      GeogCitationGeoKey (Ascii,11): "CRISM MRDR"
      GeogLinearUnitsGeoKey (Short,1): Linear_Meter
      GeogAngularUnitsGeoKey (Short,1): Angular_Degree
      GeogSemiMajorAxisGeoKey (Double,1): 3396000          
      GeogSemiMinorAxisGeoKey (Double,1): 3396000          
      ProjectedCSTypeGeoKey (Short,1): User-Defined
      ProjectionGeoKey (Short,1): User-Defined
      ProjCoordTransGeoKey (Short,1): CT_Equirectangular
      ProjLinearUnitsGeoKey (Short,1): Linear_Meter
      ProjFalseEastingGeoKey (Double,1): 0                
      ProjFalseNorthingGeoKey (Double,1): 0                
      ProjCenterLongGeoKey (Double,1): 0                
      ProjCenterLatGeoKey (Double,1): 67.5000001       
      End_Of_Keys.

It turns out the problem is because GeographicTypeGeoKey? is 0 (shown as Undefined in the report). This is treated by GDAL as a valid EPSG code and embedded in the WKT as an authority value. Note the anomolous AUTHORITY["EPSG","0"]. This gets picked up in preference to the actual spheroid parameters when writing to jpeg2000 (or geotiff which is the same for this purpose) and we end up with a file with an unlookupable GCS code which causes treatment as WGS84.

PROJCS["unnamed",
    GEOGCS["CRISM MRDR",
        DATUM["unknown",
            SPHEROID["unnamed",3396000,0]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","0"]],
    PROJECTION["Equirectangular"],
    PARAMETER["latitude_of_origin",67.5000001],
    PARAMETER["central_meridian",0],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]

As an initial improvement, I'm modifying libgeotiff to discard GCS values less than 1 which resolves the problem in this case. But I would also like to add some sanity checking in GDAL itself to deal with such situations.

Index: geo_normalize.c
===================================================================
RCS file: /cvs/maptools/cvsroot/geotiff/libgeotiff/geo_normalize.c,v
retrieving revision 1.51
diff -r1.51 geo_normalize.c
2099a2100,2101
>     if( psDefn->GCS < 1 || psDefn->GCS >= KvUserDefined )
>         psDefn->GCS = KvUserDefined;

I have applied a similar check at the GDAL level in trunk (r13641) and 1.5 branch (r13642).