[FWTools] gdal geotiff help - can't do simple affine transform..?
Mark.Amend at noaa.gov
Wed Dec 13 16:47:54 EST 2006
Hi there folks-
I need a bit of help here. I know there are other ways to do this, but
I was hoping I could do it with gdal utility tools. Here's the
situation: I have a tif (test.tif) into which I inserted two gcps as
$ gdal_translate -gcp 722.00 -14314.00 68470.3295 6115827.932 -gcp
8059.47 -1095.20 68458.758 6115826.179 -a_srs 'EPSG:32604'
Using the origin of the tif in the upper left corner (right?) the
ModelTiepointTag GCPs are listed properly in the header (at bottom of
this post). So far, so good?
I then would like to warp the tif into the PCS defined, using the GCPs
provided. The image basically needs and affine transformation to be
rotated and scaled to fit. Easy to do in ArcGIS with the Georeferencing
gdalwarp will not recognize that a first-order transformation is needed,
and even setting the flag "-order 1" doesn't work, either. I thought it
would recognize that I have two control points and thus a first-order
Here's what I get:
$ gdalwarp test.tif testutm4n.tif
ERROR 1: Failed to compute polynomial equations of desired order
for provided control points.
Am I doing something wrong? And yes, I'm after sub-centimeter pixels in
my image. Setting the -tr flag to define the output pixel resolution
doesn't make a difference.
$ listgeo test.tif
722 -14314 0
68470.329 6115827.93 0
8059.47 -1095.2 0
68458.758 6115826.18 0
GTModelTypeGeoKey (Short,1): ModelTypeProjected
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
GTCitationGeoKey (Ascii,21): "WGS 84 / UTM zone 4N"
GeogCitationGeoKey (Ascii,7): "WGS 84"
GeogAngularUnitsGeoKey (Short,1): Angular_Degree
ProjectedCSTypeGeoKey (Short,1): PCS_WGS84_UTM_zone_4N
ProjLinearUnitsGeoKey (Short,1): Linear_Meter
PCS = 32604 (WGS 84 / UTM zone 4N)
Projection = 16004 (UTM zone 4N)
Projection Method: CT_TransverseMercator
ProjNatOriginLatGeoKey: 0.000000 ( 0d 0' 0.00"N)
ProjNatOriginLongGeoKey: -159.000000 (159d 0' 0.00"W)
ProjFalseEastingGeoKey: 500000.000000 m
ProjFalseNorthingGeoKey: 0.000000 m
GCS: 4326/WGS 84
Datum: 6326/World Geodetic System 1984
Ellipsoid: 7030/WGS 84 (6378137.00,6356752.31)
Prime Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E)
Projection Linear Units: 9001/metre (1.000000m)
... unable to transform points between pixel/line and PCS space
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