[Gdal-dev] Transform from epsg:26912 to esri:102758 issue...

Jason M. Nielsen jnielsen at aero-graphics.com
Thu Sep 9 10:47:40 EDT 2004


I have data in epsg:26912 and the client wants it transformed to esri:102758.

The destination system is "NAD-1983_Stateplane_Wyoming_West_FIPS_4904_Feet"
according to ArcGIS.

If I try to do a direct transformation the following occures:

[root at mapserver s]# gdalwarp -s_srs epsg:26912 -t_srs esri:102758
south_lincoln.tif south_lincolnx.tif 
ERROR 1: Translating source or target SRS failed:
esri:102758

So instead I have specified the parameters as follows:

gdalwarp -s_srs epsg:26912 -t_srs "+proj=tmerc +lat_0=40.5
+lon_0=-110.0833333333333 +k=0.999938 +x_0=799999.9999999999 +y_0=100000
+ellps=GRS80 +datum=NAD83 +to_meter=0.3048006096012192" south_lincoln.tif
south_lincolnx.tif

Now this translates but I then have another issue. gdalinfo reports the
following which looks all good accept one thing thats bugging me.  Note the
false_easting and false_northing. The client gave me a print out of the
projection defines which included those two values. I have also confirmed the
clients printout in both ArcGIS and AutoCAD 2002. The false origin listed by the
client is as follows:

false_easting: 2624666.666667
false_northing: 328083.333333

Note that these are a factor of 3.2808 of those created during the gdal
transformation below.

[root at mapserver s]# gdalinfo south_lincolnx.tif 
Driver: GTiff/GeoTIFF
Size is 21680, 42482
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["NAD83",
        DATUM["North_American_Datum_1983",
            SPHEROID["GRS 1980",6378137,298.2572221010042,
                AUTHORITY["EPSG","7019"]],
            AUTHORITY["EPSG","6269"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4269"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",40.5],
    PARAMETER["central_meridian",-110.0833333333333],
    PARAMETER["scale_factor",0.999938],
    PARAMETER["false_easting",8611093.888888888],
    PARAMETER["false_northing",1076386.736111111],
    UNIT["US survey foot",0.3048006096012192,
        AUTHORITY["EPSG","9003"]]]
Origin = (2342073.330325,1150633.460539)
Pixel Size = (3.28217146,-3.28217146)
Corner Coordinates:
Upper Left  ( 2342073.330, 1150633.461) (131d54'38.64"W, 38d36'4.93"N)
Lower Left  ( 2342073.330, 1011200.253) (131d47'54.78"W, 38d14'45.11"N)
Upper Right ( 2413230.808, 1150633.461) (131d40'45.89"W, 38d38'47.38"N)
Lower Right ( 2413230.808, 1011200.253) (131d34'5.46"W, 38d17'25.51"N)
Center      ( 2377652.069, 1080916.857) (131d44'20.54"W, 38d26'46.05"N)


So the question is. Who's is correct? And if my output is wrong what am I doing
incorrectly or are the defines in the esri proj file incorrect? Or am I bugging
out over nothing?

Thanks,
Jason.



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