Thank you both for your answers. I have applied your suggestions.
Making a single command works but does not change the result.
Concerning the compression, I used LZW instead of NONE. However, it also
does not make any difference.
I also changed the srcwin parameters. I do not get any errors and the
gdalinfo says that the subarea is within the original area.
I skipped the png part to make it easier first. And after trying to open
the new tif with gimp and getting an error message that the float32 data
cannot be displayed I added the ot-flag. Here is my new command line:
$ gdal_translate -ot Byte -srcwin 0 0 4000 4000 -co COMPRESS=LZW
EUD_CP-DEMS_6500035000-AA.tif test.tif
What I get is a completely black tif. Here are the two gdalinfo-outputs,
that I get:
$ gdalinfo -mm EUD_CP-DEMS_6500035000-AA.tif
Driver: GTiff/GeoTIFF
Files: EUD_CP-DEMS_6500035000-AA.tif
Size is 40000, 40000
Coordinate System is:
PROJCS["ETRS89 / ETRS-LAEA",
GEOGCS["ETRS89",
DATUM["European_Terrestrial_Reference_System_1989",
SPHEROID["GRS 1980",6378137,298.2572221000027,
AUTHORITY["EPSG","7019"]],
AUTHORITY["EPSG","6258"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4258"]],
PROJECTION["Lambert_Azimuthal_Equal_Area"],
PARAMETER["latitude_of_center",52],
PARAMETER["longitude_of_center",10],
PARAMETER["false_easting",4321000],
PARAMETER["false_northing",3210000],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]],
AUTHORITY["EPSG","3035"]]
Origin = (6000000.000000000000000,4000000.000000000000000)
Pixel Size = (25.000000000000000,-25.000000000000000)
Metadata:
TIFFTAG_DOCUMENTNAME=EUD_CP-DEMS_6500035000-AA.tif
TIFFTAG_IMAGEDESCRIPTION=File written by egcs_wrgtif 2.1
TIFFTAG_SOFTWARE=IDL 8.2, Exelis Visual Information Solutions, Inc.
TIFFTAG_DATETIME=2013:09:17 21:00:27
TIFFTAG_XRESOLUTION=100
TIFFTAG_YRESOLUTION=100
TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
AREA_OR_POINT=Area
Image Structure Metadata:
COMPRESSION=LZW
INTERLEAVE=BAND
Corner Coordinates:
Upper Left ( 6000000.000, 4000000.000) ( 37d47'0.49"E, 56d 7'28.33"N)
Lower Left ( 6000000.000, 3000000.000) ( 32d47'35.21"E, 47d45'16.08"N)
Upper Right ( 7000000.000, 4000000.000) ( 51d32'27.75"E, 51d55'27.24"N)
Lower Right ( 7000000.000, 3000000.000) ( 44d57'3.39"E, 44d18'11.63"N)
Center ( 6500000.000, 3500000.000) ( 41d41'39.51"E, 50d15'46.40"N)
Band 1 Block=40000x1 Type=Float32, ColorInterp=Gray
ERROR 1: Failed to compute min/max, no valid pixels found in sampling.
$ gdalinfo -mm test.tif
Driver: GTiff/GeoTIFF
Files: test.tif
Size is 4000, 4000
Coordinate System is:
PROJCS["ETRS89 / ETRS-LAEA",
GEOGCS["ETRS89",
DATUM["European_Terrestrial_Reference_System_1989",
SPHEROID["GRS 1980",6378137,298.2572221010002,
AUTHORITY["EPSG","7019"]],
AUTHORITY["EPSG","6258"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4258"]],
PROJECTION["Lambert_Azimuthal_Equal_Area"],
PARAMETER["latitude_of_center",52],
PARAMETER["longitude_of_center",10],
PARAMETER["false_easting",4321000],
PARAMETER["false_northing",3210000],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]],
AUTHORITY["EPSG","3035"]]
Origin = (6000000.000000000000000,4000000.000000000000000)
Pixel Size = (25.000000000000000,-25.000000000000000)
Metadata:
TIFFTAG_DOCUMENTNAME=EUD_CP-DEMS_6500035000-AA.tif
TIFFTAG_IMAGEDESCRIPTION=File written by egcs_wrgtif 2.1
TIFFTAG_SOFTWARE=IDL 8.2, Exelis Visual Information Solutions, Inc.
TIFFTAG_DATETIME=2013:09:17 21:00:27
TIFFTAG_XRESOLUTION=100
TIFFTAG_YRESOLUTION=100
TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
AREA_OR_POINT=Area
Image Structure Metadata:
COMPRESSION=LZW
INTERLEAVE=BAND
Corner Coordinates:
Upper Left ( 6000000.000, 4000000.000) ( 37d47'0.49"E, 56d 7'28.33"N)
Lower Left ( 6000000.000, 3900000.000) ( 37d10'18.23"E, 55d18'7.26"N)
Upper Right ( 6100000.000, 4000000.000) ( 39d16'14.71"E, 55d46'30.54"N)
Lower Right ( 6100000.000, 3900000.000) ( 38d38'6.52"E, 54d57'38.92"N)
Center ( 6050000.000, 3950000.000) ( 38d12'51.64"E, 55d32'35.70"N)
Band 1 Block=4000x2 Type=Byte, ColorInterp=Gray
Computed Min/Max=0.000,0.000
Am 14.04.2014 19:51, schrieb Etienne Tourigny:>
On Mon, Apr 14, 2014 at 11:16 AM, Nicole Stoffels <stoff...@f2e.de
<mailto:stoff...@f2e.de>> wrote:
Dear Gdal-List,
I have a large ASTER file (downloaded from
http://www.eea.europa.eu/data-__and-maps/data/eu-dem#tab-__european-data
<http://www.eea.europa.eu/data-and-maps/data/eu-dem#tab-european-data>)
in the GeoTIFF-format. It is compressed with LZW. What I want to do is:
1. unpack it
2. seperate a smaller region from it
3. convert this regional GeoTIFF to a PNG
What I am doing:
$ gdal_translate -co COMPRESS=NONE EUD_CP-DEMS_6500035000-AA.tif
tmp1.tif
$ gdal_translate -srcwin 6500 3300 1000 1000 tmp1.tif tmp2.tif
$ gdal_translate -of PNG tmp2.tif tmp2.png
When I display the info with gdalinfo the first step seems to
produce a decompressed file. The line COMPRESSION=LZW is not there
anymore.
You need to set the compression options on any gdal command, it does not
use the compression of the input file. Also, you specifically asked for
no compression, so it's doing what you told it to.
use "-co COMPRESS=LZW"
However, if I want to display the min and max with gdalinfo, I get
the following error.
ERROR 1: Failed to compute min/max, no valid pixels found in sampling.
try without changing the extents and see if a single command (as
suggested by Jean-Luc) works
I thought that the file might be too large, but if I change the
data_type from float 32 to e.g. Int16 I get 0 as min and max value.
That's why I assume that already the first gdal_translate does not
work as I actually want it to work.
your input values are probably between 0 and 1 in this case
The other two transformations work without error messages. However,
in the end I get a black png.
I have tried all types of transformation with various options. But
as I am new in the subject and do not know much about gdal, I have
no further ideas how to generate a file from my large GeoTIFF to
continue working with.
I hope someone has an idea, what's going wrong with my
gdal_translations. Thanks very much in advance.
Best regards
Nicole
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