[gdal-dev] Strange errors with large vrt

[yvecai]

I'm trying to make a world-wide hillshade dataset filling SRTM void from 
Aster, and using Aster data only between 60°N and 72°N.
I computed all 1x1° hillshade tiles, but now I'm struggling to work with 
a vrt.
If I make a .vrt of all ~29'000 single 1x1° tiles, I don't have any data 
above 60°N, neither with Mapnik gdal datasource, nor gdal_translate, nor 
gdal2tiles.
But if I make a small 38-files .vrt around 60°N, gdal_translate with a 
-projwin works well.

Maybe someone can see a difference between hillshade2_N58E164.tif and 
hillshade2_N63E164.tif ? See gdalinfo below, I don't.
Also, vrt files and some tiles can be found at 
http://www.pistes-nordiques.org/download/extract.zip (16MB).

Yves

GDAL 1.9.1, released 2012/05/15

$ gdalinfo extract/hillshade2_N58E164.tif
Driver: GTiff/GeoTIFF
Files: extract/hillshade2_N58E164.tif
Size is 786, 1505
Coordinate System is:
PROJCS["unnamed",
     GEOGCS["unnamed ellipse",
         DATUM["unknown",
             SPHEROID["unnamed",6378137,0]],
         PRIMEM["Greenwich",0],
         UNIT["degree",0.0174532925199433]],
     PROJECTION["Mercator_1SP"],
     PARAMETER["central_meridian",0],
     PARAMETER["scale_factor",1],
     PARAMETER["false_easting",0],
     PARAMETER["false_northing",0],
     UNIT["metre",1,
         AUTHORITY["EPSG","9001"]]]
Origin = (18256303.723854541778564,8180567.003424840979278)
Pixel Size = (141.656454553493091,-141.656454553493091)
Metadata:
   AREA_OR_POINT=Area
   TIFFTAG_DOCUMENTNAME=slopes/hillshade2_N58E164.tif
   TIFFTAG_RESOLUTIONUNIT=1 (unitless)
   TIFFTAG_XRESOLUTION=72
   TIFFTAG_YRESOLUTION=72
Image Structure Metadata:
   COMPRESSION=DEFLATE
   INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left  (18256303.724, 8180567.003) (163d59'57.00"E, 59d 0' 3.00"N)
Lower Left  (18256303.724, 7967374.039) (163d59'57.00"E, 58d 0' 0.97"N)
Upper Right (18367645.697, 8180567.003) (164d59'57.73"E, 59d 0' 3.00"N)
Lower Right (18367645.697, 7967374.039) (164d59'57.73"E, 58d 0' 0.97"N)
Center      (18311974.710, 8073970.521) (164d29'57.36"E, 58d30'14.82"N)
Band 1 Block=786x1505 Type=Byte, ColorInterp=Gray
   Mask Flags: PER_DATASET ALPHA
Band 2 Block=786x1505 Type=Byte, ColorInterp=Alpha
$ gdalinfo extract/hillshade2_N63E164.tif
Driver: GTiff/GeoTIFF
Files: extract/hillshade2_N63E164.tif
Size is 692, 1551
Coordinate System is:
PROJCS["unnamed",
     GEOGCS["unnamed ellipse",
         DATUM["unknown",
             SPHEROID["unnamed",6378137,0]],
         PRIMEM["Greenwich",0],
         UNIT["degree",0.0174532925199433]],
     PROJECTION["Mercator_1SP"],
     PARAMETER["central_meridian",0],
     PARAMETER["scale_factor",1],
     PARAMETER["false_easting",0],
     PARAMETER["false_northing",0],
     UNIT["metre",1,
         AUTHORITY["EPSG","9001"]]]
Origin = (18256381.029056482017040,9349799.443527495488524)
Pixel Size = (160.906779712378437,-160.906779712378437)
Metadata:
   AREA_OR_POINT=Area
   TIFFTAG_DOCUMENTNAME=slopes/hillshade2_N63E164.tif
   TIFFTAG_RESOLUTIONUNIT=1 (unitless)
   TIFFTAG_XRESOLUTION=72
   TIFFTAG_YRESOLUTION=72
Image Structure Metadata:
   COMPRESSION=DEFLATE
   INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left  (18256381.029, 9349799.444) (163d59'59.50"E, 64d 0' 0.50"N)
Lower Left  (18256381.029, 9100233.028) (163d59'59.50"E, 62d59'59.74"N)
Upper Right (18367728.521, 9349799.444) (165d 0' 0.41"E, 64d 0' 0.50"N)
Lower Right (18367728.521, 9100233.028) (165d 0' 0.41"E, 62d59'59.74"N)
Center      (18312054.775, 9225016.236) (164d29'59.95"E, 63d30'15.88"N)
Band 1 Block=692x1551 Type=Byte, ColorInterp=Gray
   Mask Flags: PER_DATASET ALPHA
Band 2 Block=692x1551 Type=Byte, ColorInterp=Alpha