[gdal-dev] Using VRT images with derived bands (pixel function)
yjacolin at free.fr
Thu Feb 16 03:31:11 EST 2012
I am using such application stack: netcdf > vrt and pixel functions > GDAL >
We have a tiled layer inside PostGIS and we juste configure the layer like all
other tiled datasource:
CONNECTION "dbname=mydb host=localhost user=myUser password=mypassword"
DATA "the_geom FROM myLayer USING srid=4326"
"wms_timeitem" "datetime" #column in postgis table of type timestamp
If you want to use the vrt file directly it is also possible as easily as:
About register the plugin, in Apache config you have to use SetEnv this way:
SetEnv GDAL_DRIVER_PATH directory/mapserver/misc
SetEnv MS_MAPFILE directory/mapserver/mymapfile.map
SetEnv MS_MAPFILE_PATTERN "^directory/mapserver/mymapfile.map"
Le Mercredi 15 Février 2012 19:52:21 Armin Burger a écrit :
> Dear all
> I would be interested in using VRT images with "derived bands" as
> described on the VRT image documentation page. This requires the
> definition of a pixel function and the registration of this function in
> the used application via "GDALAddDerivedBandPixelFunc".
> The provided sample function is already towards what I'm looking for. I
> would just need to adapt it accordingly (calculating band 1 as
> combination of source band 1 and 3).
> Since my main interest is to use such image definition in the context of
> Mapserver, my question is if there could be a way to use this also from
> Mapserver as application? If yes, where would I need to register the
> function and how would I best make the function available to Mapserver
> (maybe via an .o file that is created when compiling)? Maybe somewhere
> inside mapgdal.c ?
> Would such a pixel function be used also in case when not the full
> resolution image (i.e. TIFF file referenced in the VRT file) is read but
> one of the overviews from the .ovr file associated to the Tiff file?
> Thanks in advance for any hints
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
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