[Gdal-dev] Help handling image with gcp.

[Ken Sewell]

I just started receiving some NITF files that only have GCP's.  I need the
ability to query the pixel's lat/lon.  Can I do this with GCP's or is
there a utility in GDAL that will georegister the image from the GCP?
This what gdalinfo shows:

Driver: NITF/National Imagery Transmission Format
Size is 640, 473
Coordinate System is `'
GCP Projection = GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS
84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","
6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9108"]],AXIS["Lat",NORTH],AXIS["Long",EAST],AUTHORI
TY["EPSG","4326"]]
GCP[  0]: Id=UpperLeft, Info=
          (0,0) -> (-116.633,35.2542,0)
GCP[  1]: Id=UpperRight, Info=
          (640,0) -> (-116.66,35.2758,0)
GCP[  2]: Id=LowerLeft, Info=
          (0,473) -> (-116.608,35.2736,0)
GCP[  3]: Id=LowerRight, Info=
          (640,473) -> (-116.624,35.2889,0)
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,  473.0)
Upper Right (  640.0,    0.0)
Lower Right (  640.0,  473.0)
Center      (  320.0,  236.5)
Band 1 Block=640x1 Type=Byte, ColorInterp=Undefined


Ken Sewell                   Defense Research Associates
Project Engineer             3915 Germany Lane, Suite 102
937-656-4899 x3004           Beavercreek, Ohio 45431-1608
sewell at dramail.com