[Geotiff] Re: How to add a projection to GeoTIFF?

[Frank Warmerdam]

Bruce,

I have committed CEA support in libgeotiff, and produced
a test example dataset at: 

 ftp://ftp.remotesensing.org/geotiff/samples/gdal_eg

The supporting information file with the projection looks like
this:


Cyldindrical Equal Area
-----------------------

Frank Warmerdam
warmerdam at pobox.com

Created by reprojecting utm11-27.tif in pci_eg directory.

Geotiff_Information:
   Version: 1
   Key_Revision: 1.0
   Tagged_Information:
      ModelTiepointTag (2,3):
         0                0                0                
         -28493.1668      4255884.54       0                
      ModelPixelScaleTag (1,3):
         60.022137        60.022137        0                
      End_Of_Tags.
   Keyed_Information:
      GTModelTypeGeoKey (Short,1): ModelTypeProjected
      GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
      GTCitationGeoKey (Ascii,8): "unnamed"
      GeographicTypeGeoKey (Short,1): GCS_NAD27
      GeogCitationGeoKey (Ascii,6): "NAD27"
      GeogAngularUnitsGeoKey (Short,1): Angular_Degree
      ProjectedCSTypeGeoKey (Short,1): User-Defined
      ProjectionGeoKey (Short,1): User-Defined
      ProjCoordTransGeoKey (Short,1): CT_CylindricalEqualArea
      ProjLinearUnitsGeoKey (Short,1): Linear_Meter
      ProjStdParallel1GeoKey (Double,1): 33.75            
      ProjNatOriginLongGeoKey (Double,1): -117.333333      
      ProjFalseEastingGeoKey (Double,1): 0                
      ProjFalseNorthingGeoKey (Double,1): 0                
      End_Of_Keys.
   End_Of_Geotiff.

Projection Method: CT_CylindricalEqualArea
   ProjStdParallel1GeoKey: 33.750000 ( 33d45' 0.00"N)
   ProjNatOriginLongGeoKey: -117.333333 (117d20' 0.00"W)
   ProjFalseEastingGeoKey: 0.000000 m
   ProjFalseNorthingGeoKey: 0.000000 m
GCS: 4267/NAD27
Datum: 6267/North American Datum 1927
Ellipsoid: 7008/Clarke 1866 (6378206.40,6356583.80)
Prime Meridian: 8901/Greenwich (0.000000/  0d 0' 0.00"E)
Projection Linear Units: 9001/metre (1.000000m)

Corner Coordinates:
Upper Left    (  -28493.167, 4255884.544)  (117d38'28.21"W, 33d54'13.08"N)
Lower Left    (  -28493.167, 4224973.143)  (117d38'28.21"W, 33d37'30.66"N)
Upper Right   (    2358.212, 4255884.544)  (117d18'28.28"W, 33d54'13.08"N)
Lower Right   (    2358.212, 4224973.143)  (117d18'28.28"W, 33d37'30.66"N)
Center        (  -13067.478, 4240428.844)  (117d28'28.24"W, 33d45'51.47"N)

>From gdalinfo:

Driver: GTiff/GeoTIFF
Size is 514, 515
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["NAD27",
        DATUM["North_American_Datum_1927",
            SPHEROID["Clarke 1866",6378206.4,294.9786982138982,
                AUTHORITY["EPSG","7008"]],
            AUTHORITY["EPSG","6267"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4267"]],
    PROJECTION["Cylindrical_Equal_Area"],
    PARAMETER["standard_parallel_1",33.75],
    PARAMETER["central_meridian",-117.333333333333],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-28493.166784,4255884.543802)
Pixel Size = (60.02213698,-60.02213698)
Corner Coordinates:
Upper Left  (  -28493.167, 4255884.544) (117d38'28.21"W, 33d54'13.08"N)
Lower Left  (  -28493.167, 4224973.143) (117d38'28.21"W, 33d37'30.66"N)
Upper Right (    2358.212, 4255884.544) (117d18'28.28"W, 33d54'13.08"N)
Lower Right (    2358.212, 4224973.143) (117d18'28.28"W, 33d37'30.66"N)
Center      (  -13067.478, 4240428.844) (117d28'28.24"W, 33d45'51.47"N)
Band 1 Block=514x15 Type=Byte, ColorInterp=Gray

This should all appear in libgeotiff 1.2.3 when released.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent