[gdal-dev] Wrong metadata or gdalinfo weakness (on Landsat scene over Madagascar)?

[Even Rouault]

Selon Nikos Alexandris <nik at nikosalexandris.net>:

GDAL is doing its job great on this case. The data is just oddly georeferenced,
but the end result is OK if you look at the corner coordinates in longitude,
latitude. The projection is UTM north, but with with negative y values, which
means it is on the southern hemisphere. For a GEOTIFF GDAL will not look at the
text files that might be or not be along the .TIF files. It will only look at
the geotiff tags.


> For the Landsat scene over Madagascar LE71610762013070PFS00, gdalinfo reports
> UTM Zone 38N (EPSG:32638, <http://spatialreference.org/ref/epsg/32638/>).
> This
> is wrong. It should be UTM Zone 38 _S_ (EPSG:32738,
> <http://spatialreference.org/ref/epsg/32738/>).
>
> Is it the metadata's fault or is gdalinfo wrongly guessing?  Any help?
>
>
> The scene contains in its (old) metadata file (that is the
> LE71610762013070PFS00_MTLold.txt file):
>
> ,--%<---
> GROUP = PROJECTION_PARAMETERS
>     REFERENCE_DATUM = "WGS84"
>     REFERENCE_ELLIPSOID = "WGS84"
>     GRID_CELL_SIZE_PAN = 15.000
>     GRID_CELL_SIZE_THM = 30.000
>     GRID_CELL_SIZE_REF = 30.000
>     ORIENTATION = "NUP"
>     RESAMPLING_OPTION = "CC"
>     SCAN_GAP_INTERPOLATION = 2
>     MAP_PROJECTION = "UTM"
>   END_GROUP = PROJECTION_PARAMETERS
>   GROUP = UTM_PARAMETERS
>     ZONE_NUMBER = 38
>   END_GROUP = UTM_PARAMETERS
> `--->%--
>
>
> The newer version of the metadata file reports:
>
> ,--%<---
> GROUP = PROJECTION_PARAMETERS
>     MAP_PROJECTION = "UTM"
>     DATUM = "WGS84"
>     ELLIPSOID = "WGS84"
>     UTM_ZONE = 38
>     GRID_CELL_SIZE_PANCHROMATIC = 15.00
>     GRID_CELL_SIZE_REFLECTIVE = 30.00
>     GRID_CELL_SIZE_THERMAL = 30.00
>     ORIENTATION = "NORTH_UP"
>     RESAMPLING_OPTION = "CUBIC_CONVOLUTION"
>     SCAN_GAP_INTERPOLATION = 2.0
>   END_GROUP = PROJECTION_PARAMETERS
> `--->%--
>
>
> No sign of Northern or Southern hemisphere reference. Reporting on the scene
> by using gdalinfo:
>
> ,--%<---
> gdalinfo -nomd LE71610762013070PFS00_B1.TIF -proj4
>
> Driver: GTiff/GeoTIFF
> Files: LE71610762013070PFS00_B1.TIF
> Size is 8041, 6961
> Coordinate System is:
> PROJCS["WGS 84 / UTM zone 38N",
>     GEOGCS["WGS 84",
>         DATUM["WGS_1984",
>             SPHEROID["WGS 84",6378137,298.257223563,
>                 AUTHORITY["EPSG","7030"]],
>             AUTHORITY["EPSG","6326"]],
>         PRIMEM["Greenwich",0],
>         UNIT["degree",0.0174532925199433],
>         AUTHORITY["EPSG","4326"]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["latitude_of_origin",0],
>     PARAMETER["central_meridian",45],
>     PARAMETER["scale_factor",0.9996],
>     PARAMETER["false_easting",500000],
>     PARAMETER["false_northing",0],
>     UNIT["metre",1,
>         AUTHORITY["EPSG","9001"]],
>     AUTHORITY["EPSG","32638"]]
> PROJ.4 string is:
> '+proj=utm +zone=38 +datum=WGS84 +units=m +no_defs '
> Origin = (185385.000000000000000,-2452185.000000000000000)
> Pixel Size = (30.000000000000000,-30.000000000000000)
> Corner Coordinates:
> Upper Left  (  185385.000,-2452185.000) ( 41d56'59.71"E, 22d 8'46.86"S)
> Lower Left  (  185385.000,-2661015.000) ( 41d54'25.45"E, 24d 1'48.22"S)
> Upper Right (  426615.000,-2452185.000) ( 44d17'17.50"E, 22d10'24.01"S)
> Lower Right (  426615.000,-2661015.000) ( 44d16'41.43"E, 24d 3'34.61"S)
> Center      (  306000.000,-2556600.000) ( 43d 6'20.60"E, 23d 6'24.43"S)
> Band 1 Block=8041x1 Type=Byte, ColorInterp=Gray
> `--->%--
>
> This is obviously wrong. It should be UTM Zone 38 _S_ (not _N_). That is EPSG
> 32738 <http://spatialreference.org/ref/epsg/32738/> (and not 32638
> <http://spatialreference.org/ref/epsg/32638/>).
>
> Thanks, Nikos
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