[gdal-dev] Problems with gdalwarp re-projecting from lat-long to Lambert Conformal

Bill Hudspeth wbhk at unm.edu
Mon Mar 1 13:12:40 EST 2010


Hello,

I am having problems re-projecting an ArcAscii Grid from LatLong/WGS84
to Lambert Conformal. The source grid was derived from a GRASS mapset.


Using r.out.gdal, a GRASS raster was exported to AAIGrid format using:


r.out.gdal input=MODIS_input_raster format=AAIGrid type=UInt16
output=MODIS_output_latlong.asc

The resulting grid has the following projection parameters:

Driver: AAIGrid/Arc/Info ASCII Grid
Size is 5039, 3244
Coordinate System is:
GEOGCS["GCS_WGS_1984",
    DATUM["WGS_1984",
        SPHEROID["wgs84",6378137,298.257223563]],
    PRIMEM["Greenwich",0],
    UNIT["Degree",0.017453292519943295]]
Origin = (-130.004289,47.007502)
Pixel Size = (0.00833565,-0.00833565)
Corner Coordinates:
Upper Left  (-130.0042888,  47.0075018) (130d 0'15.44"W, 47d 0'27.01"N)
Lower Left  (-130.0042888,  19.9666571) (130d 0'15.44"W, 19d57'59.97"N)
Upper Right ( -88.0009546,  47.0075018) ( 88d 0'3.44"W, 47d 0'27.01"N)
Lower Right ( -88.0009546,  19.9666571) ( 88d 0'3.44"W, 19d57'59.97"N)
Center      (-109.0026217,  33.4870795) (109d 0'9.44"W, 33d29'13.49"N)
Band 1 Block=5039x1 Type=Int16, ColorInterp=Undefined
  NoData Value=255

When I try to re-project the exported AAIGrid to another projection, I
use:

gdalwarp -s_srs EPSG:4326 -t_srs '+proj=lcc +lat__1=33n +lat_2=45n
+lon_0=97w' MODIS_output_latlong.asc MODIS_output_lambert.asc

While the resultant projection information looks correct,

Driver: GTiff/GeoTIFF
Size is 5576, 4283
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["unknown",
            SPHEROID["unnamed",6378137,298.2572235629972]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Lambert_Conformal_Conic_2SP"],
    PARAMETER["standard_parallel_1",33],
    PARAMETER["standard_parallel_2",45],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",-97],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-3540115.789204,5964029.040523)
Pixel Size = (811.62081646,-811.62081646)
Metadata:
  AREA_OR_POINT=Area
Corner Coordinates:
Upper Left  (-3540115.789, 5964029.041) (142d23'11.19"W, 42d57'29.68"N)
Lower Left  (-3540115.789, 2487857.084) (128d 1'12.16"W, 14d47'2.22"N)
Upper Right (  985481.883, 5964029.041) ( 83d18'11.06"W, 50d22'40.86"N)
Lower Right (  985481.883, 2487857.084) ( 88d 2'31.57"W, 19d32'55.81"N)
Center      (-1277316.953, 4225943.062) (110d59'51.34"W, 34d30'30.05"N)
Band 1 Block=5576x1 Type=Int16, ColorInterp=Gray



The resultant text file has only the following on the top line:

II*

and possibly with lots of binary characters at the bottom.

Thanks much for any help...

Bill





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