[Gdal-dev] Re: GDAL and Spot Vegetation
neteler at itc.it
Wed Aug 18 10:56:19 EDT 2004
On Wed, Aug 18, 2004 at 04:45:56PM +0200, Vincent Schut wrote:
> Hi Markus (cc-ing the gdal list; people might be interested in this :-),
> indeed gdal doesn't read any geographic info that might be in the hdr file
> (actually I don't know if there is some...).
Using HDFLook I was able to extract from 0001_NDV.HDF
1: ( 5601 x 8177 ) PIXEL DATA
Set no 0: Rank: 2, 5601 x 8177
Data set name: 'PIXEL DATA'
Data type: 8-bit unsigned integer
Number of attributes: 1
valid_range: 0, 255
Global attributes: 0
2:[VD] ( 3 x 40) NDVI : IMAGE INFORMATION
fieldname_list: IMAGE INFORMATION
n_records : 3
data_size : 40
VFnfields : 1
01[field] name: IMAGE INFORMATION (8-bit character) size: 40 order: 40
Global attributes: 0
3:[VD] ( 2 x 40) NDVI : CALIBRATION PARAMETERS
File size 40X2 Show size 0 -> 40 X 0 -> 2
MAP_PROJ_NAME PLATE_CARREE_1KMG nom provisoirement egal au code
GEODETIC_SYST_NAME WGS 1984
> What I did was using a 'vgt_unzip' script,which did the following if I
> remember well:
> - parse the .zip filename for the region and the date, and store these
So one seems to have to parse the 0001_LOG.TXT (sigh).
> - unzip the file into a temp directory (all vegetation zip files unzip in the
> same 0001/ directory, handy that is :-/ )
> - copy the right vrt file (for that region) to this temp dir. I created vrt
> file for the 2 regions I used, which I kept in a 'vrt_templates' dir; the vrt
> files refer to the vgt hdr files with relative path names (a feature Frank
> Warmerdam implemented especially for this purpose on my request), thus they
> become meaningfull when copied to a dir with the right .hdr files.)
> - gdaltranslate this vrtfile to a geotiff file, giving the geotiff file some
> meaningfull name like $region_$date_s10.tif or something like that
> - copy this geotiff file (if everyting went OK) to a spotveg data dir, which
> will contain all these geotiff files in the end.
> empty and remove the temp dir.
> I can't seem to find the script right now, should have it somewhere around
> here but haven't used it for some time. But using the above guidelines you
> should be able to write your own. Mine was not very fancy & robust, either...
OK, thanks for your insights.
> On Wednesday 18 August 2004 14:46, you wrote:
> > Hi Vincent,
> > while digging in the GDAL archive I came across this
> > message:
> > http://xserve.flids.com/pipermail/gdal-dev/2004-March/005134.html
> > Did you ever manage to read the SPOT Vegetation NDVI
> > data as available from http://free.vgt.vito.be/?
> > The file of interest seems to be
> > 0001_NDV.HDF
> > but GDAL only outputs xy pixels...
> > Maybe you have a receipt using VRT?
> > Thanks in advance
> > Markus
> Vincent Schut
> SarVision B.V.
> Wageningen, The Netherlands
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