should CT_Mercator fallback to looking for ProjStdParallel1GeoKey?

[warmerdam]

The GDAL 1.8-esri branch has the following in gt_wkt_srs.cpp:

          case CT_Mercator:
            if(adfParm[0] == 0.0)
            {
              double v;
              if( GTIFKeyGet(hGTIF, ProjStdParallel1GeoKey, &v, 0, 1 ) )
                adfParm[0] = v;
            }
            oSRS.SetMercator( adfParm[0], adfParm[1],
                              adfParm[4],
                              adfParm[5], adfParm[6] );

The implication is that ProjStdParallel1 ought to be treated as a fallback for ProjNatOriginLatGeoKey in GTIFFFetchProjParms() in geo_normalize.c. Setting up this ticket to consider this.

[warmerdam]

I have reviewed this and decide not to pursue this without some justification.