[Qgis-user] Raster (geotif): discrepancy between gdalinfo and qgis metadata

[Agustin Lobo]

At reading file test2.tif (use pseudocolor for visualization), which
is available here
http://sites.google.com/site/eospansite/dummy/test2.tif
(sometimes the direct link does not work, in such a case point your browser
to http://sites.google.com/site/eospansite/dummy
and find the file, the 3rd one starting from the bottom)

the file info issued by gdalinfo (using QGIS plugin
Raster/Information) is different than the one offered by QGIS under
Raster Layer Properties/Metadata. The file was created by QGIS plugin
Interpolation
out of a vector points file in ED50 UTM31N projection. The fact is that
the orientation in QGIS is correct, while R follows the info given by gdal and
the image is reversed. Note that QGIS states the origin in the NW
corner and then
sets negative Y resolution. But this is not what gdalinfo reads.

Details:

gdalinfo test2.tif
Driver: GTiff/GeoTIFF
Files: test2.tif
Size is 256, 256
Coordinate System is:
PROJCS["ED50 / UTM zone 31N",
    GEOGCS["ED50",
        DATUM["European_Datum_1950",
            SPHEROID["International 1924",6378388,297.000000000005,
                AUTHORITY["EPSG","7022"]],
            AUTHORITY["EPSG","6230"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4230"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",3],
    PARAMETER["scale_factor",0.9996],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]],
    AUTHORITY["EPSG","23031"]]
Origin = (424389.000000000000000,4635822.000000000000000)
Pixel Size = (345.007812500000000,194.019531250000000)
Metadata:
  AREA_OR_POINT=Area
Image Structure Metadata:
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  (  424389.000, 4635822.000) (  2d 5'20.10"E, 41d52'11.88"N)
Lower Left  (  424389.000, 4685491.000) (  2d 4'56.97"E, 42d19'2.06"N)
Upper Right (  512711.000, 4635822.000) (  3d 9'11.42"E, 41d52'24.52"N)
Lower Right (  512711.000, 4685491.000) (  3d 9'15.31"E, 42d19'14.90"N)
Center      (  468550.000, 4660656.500) (  2d37'10.89"E, 42d 5'47.83"N)
Band 1 Block=256x4 Type=Float64, ColorInterp=Gray

while QGIS Raster Layer Properties/Metadata states:
Layer Spatial Reference System:
+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs
Origin:
424389,4.68549e+06
Pixel Size:
279.887,-279.887



--
Dr. Agustin Lobo
Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
Lluis Sole Sabaris s/n
08028 Barcelona
Spain
Tel. 34 934095410
Fax. 34 934110012
e-mail Agustin.Lobo at ija.csic.es
http://www.ija.csic.es/gt/obster