GDAL ignores the calibration data when the ul,lr corner is (0,0)

[jcrepetto]

I have downloaded a bitmap file of the world ( http://veimages.gsfc.nasa.gov//2433/land_shallow_topo_2048.tif)

I have translated the south-earth quarter of this map to ECW :

gdal_translate -of ECW -co TARGET=88% -co DATUM=WGS84 -co PROJ=GEODETIC -a_ullr 0 0 180 -90 -srcwin 1024 512 1024 512 land_shallow_topo_2048.tif south_east.ecw

The ECW file is correct. But GDAL fails to read the calibration data (origin and pixel size) :

$ gdalinfo south_east.ecw

Driver: ECW/ERMapper Compressed Wavelets
Size is 1024, 512
Coordinate System is:
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],
    AUTHORITY["EPSG","4326"]]
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,  512.0)
Upper Right ( 1024.0,    0.0)
Lower Right ( 1024.0,  512.0)
Center      (  512.0,  256.0)
Band 1 Block=1024x1 Type=Byte, ColorInterp=Red
  Overviews: arbitrary
Band 2 Block=1024x1 Type=Byte, ColorInterp=Green
  Overviews: arbitrary
Band 3 Block=1024x1 Type=Byte, ColorInterp=Blue
  Overviews: arbitrary

Patch proposal (for GDAL 1.4.2):

--- frmts/ecw/ecwdataset.cpp.orig	2007-10-24 11:35:44.000000000 +0200
+++ frmts/ecw/ecwdataset.cpp	2007-10-24 11:41:59.000000000 +0200
@@ -1539,9 +1539,9 @@
 
     if( psFileInfo->fOriginX != 0.0 
         || psFileInfo->fOriginY != 0.0 
-        && (psFileInfo->fCellIncrementX != 0.0 && 
+        || (psFileInfo->fCellIncrementX != 0.0 && 
             psFileInfo->fCellIncrementX != 1.0)
-        && (psFileInfo->fCellIncrementY != 0.0 && 
+        || (psFileInfo->fCellIncrementY != 0.0 && 
             psFileInfo->fCellIncrementY != 1.0) )
     {
         bGeoTransformValid = TRUE;

BTW, there may be a similar bug in other drivers, for example the TIFF driver (please read < http://lists.maptools.org/pipermail/gdal-dev/2007-July/013497.html>). The source code of the other drivers should be reviewed.

[warmerdam]

Mateusz,

Could you look into this? The only scenario that should be treated as not a valid geotransform is an origin at 0,0 and an increment of 1/1.

[mloskot]

Frank,

This ticket has been omitted for 1.4.3, probably because unintentionally it's not assigned to any milestone. Should it be assigned to 1.4.3?

[warmerdam]

This was deliberately not request in 1.4. The problem is relatively minor, and the risk of screwing stuff up is significant if there is an unexpected side effect to a change.

[warmerdam]

Boosting priority at the request of Jean-Claude Repetto.

[warmerdam]

Agreed, patch applied in trunk (r14008) and 1.5 branch (r14009) just in time for 1.5.1RC2.

I have not created any regression test for this issue, nor actually tried it out. I'm applying the code change based on just a visual review.