Mercator, NAD27

In EASI/PACE we have a "central meridian", which is corresponded with
the NatOriginLong value, and a "latitude of true scale" which is 
corresponded with the NatOriginLat.  We don't have a scale, so I am 
assuming that the scale is always 1.0 at the latitude of true scale.
We don't import Mercator if the scale is other than 1.0.

What is called CenterEasting and CenterNorthing in this projection is
just the normal FalseEasting and FalseNorthing in EASI/PACE.

Frank Warmerdam
warmerda@pci.on.ca


Added Note, Jan/99:

According to the working notes on CT_Mercator, it is supposed to 
have the normal false northing and easting keys, not ProjCenterEasting
and ProjCenterNorthing.  Files generated by Oasis montaj (see ../from_gxf)
are correct in this regard, though PCI files are still generated 
incorrectly as below.

Frank Warmerdam
warmerda@home.com




Geotiff_Information:
   Version: 1
   Key_Revision: 1.0
   Tagged_Information:
      ModelTiepointTag (2,3):
         0                0                0                
         -15436.3858      3321987.86       0                
      ModelPixelScaleTag (1,3):
         60               60               0                
      End_Of_Tags.
   Keyed_Information:
      GTModelTypeGeoKey (Short,1): ModelTypeProjected
      GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
      GTCitationGeoKey (Ascii,17): "MER         E000"
      GeographicTypeGeoKey (Short,1): GCS_NAD27
      GeogLinearUnitsGeoKey (Short,1): Linear_Meter
      GeogAngularUnitsGeoKey (Short,1): Angular_Degree
      ProjectedCSTypeGeoKey (Short,1): User-Defined
      ProjectionGeoKey (Short,1): User-Defined
      ProjCoordTransGeoKey (Short,1): CT_Mercator
      ProjLinearUnitsGeoKey (Short,1): Linear_Meter
      ProjNatOriginLongGeoKey (Double,1): -117.474543      
      ProjNatOriginLatGeoKey (Double,1): 33.764462        
      ProjCenterEastingGeoKey (Double,1): 0                
      ProjCenterNorthingGeoKey (Double,1): 0                
      ProjScaleAtNatOriginGeoKey (Double,1): 1                
      End_Of_Keys.
   End_Of_Geotiff.


PROREP  Georeference Segment Report             V6.0 EASI/PACE  14:52 28-Nov-95
 
../projdemo/MER.pix                     [S    1BIC     515P     515L] 07-Nov-95

   1:GEOref    Type:150 [Georeferencing        ]   Last Update:  5:04 07-Nov-95
     Contents: Master Georeferencing Segment for File                          

 Output Georeferenced Units     :    MER         E000
 Projection                     :    Mercator                                
 Earth Ellipsoid                :    Clarke 1866 (NAD 27)  
 Upper Left  Corner             :          -15436.386 E         3321987.862 N  
 Upper Right Corner             :           15463.614 E         3321987.862 N  
 Image Centre                   :              13.614 E         3306537.862 N  
 Lower Left  Corner             :          -15436.386 E         3291087.862 N  
 Lower Right Corner             :           15463.614 E         3291087.862 N  
 Pixel Size                     :              60.000 E              60.000 N  

 Upper Left  Corner             :    117d38'28.21" W  Lon   33d54'13.08" N  Lat
 Upper Right Corner             :    117d18'27.44" W  Lon   33d54'13.08" N  Lat
 Image Centre                   :    117d28'27.82" W  Lon   33d45'52.03" N  Lat
 Lower Left  Corner             :    117d38'28.21" W  Lon   33d37'30.15" N  Lat
 Lower Right Corner             :    117d18'27.44" W  Lon   33d37'30.15" N  Lat

 Reference Longitude/Latitude   :    117d28'28.35" W  Lon   33d45'52.06" N  Lat