Re: [gdal-dev] Strange errors with large vrt

2012-10-09 Thread yvecai 

On 10/09/2012 08:45 PM, Even Rouault wrote:
Did you check that there was no error or warning reported when 
building the VRT ? 

There is no warning from gdalbuiltvrt, is there a flag for a verbose mode?

What do you mean by "I don't have any data" ? Do you mean that if you 
do an extraction from that VRT, you get no significant data ? 
If I make a crop with gdal_translate I only have a hillshade from the 
areas originating from SRTM, but not from the Aster areas. The result of 
gdal_translate is empty above 61°N.
Obviously this could come from the fact I used to distinct step to 
generate hillshade files for SRTM and then for Aster, but I can't see no 
differences between them ??


What does gdalinfo report on the generated VRT ? Does it reported 
extent goes above 60° ? 

Should be ok:

   Corner Coordinates:
   Upper Left  (-20037508.316,17822038.826) (180d 0' 0.00"W, 83d 0' 0.50"N)
   Lower Left  (-20037508.316,-11402298.645) (180d 0' 0.00"W, 71d 0'
   0.28"S)
   Upper Right (20037428.628,17822038.826) (179d59'57.42"E, 83d 0' 0.50"N)
   Lower Right (20037428.628,-11402298.645) (179d59'57.42"E, 71d 0' 0.28"S)
   Center  ( -39.844, 3209870.091) (  0d 0' 1.29"W, 27d41'21.83"N)



Maybe someone can see a difference between hillshade2_N58E164.tif and
hillshade2_N63E164.tif ? See gdalinfo below, I don't.

I don't see any difference... But all the files you provided in the archive are
definitely odd : their first band is set to 0. Only the 2nd band (alpha band=
has non uniform data. So that might explain what you saw with the huge .vrt
This is intended to build a hillshade overlay for webmaps, hence the 
black + alpha.

Also, vrt files and some tiles can be found at
http://www.pistes-nordiques.org/download/extract.zip (16MB).

No VRT files in that zip.

http://www.pistes-nordiques.org/download/small.vrt
http://www.pistes-nordiques.org/download/big.vrt

Yves
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[gdal-dev] Strange errors with large vrt

2012-10-09 Thread 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


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