Le dimanche 23 août 2015 14:18:03, Andrea Peri a écrit : > Hi Even, > > I just notice that in the page > http://www.gdal.org/gdalinfo.html > > In the sample reported is write a bloc size of 512x16: > >Band 1 Block=512x16 Type=Byte, ColorInterp=Gray > > Should it be a typo error ?
There's no typo. It is a TIFF with strip organization since the block width is the raster width. There are various shapes of blocks : - rectangular (typically square) blocks. e.g a tiled TIFF - blocks whose width is the raster width. e.g. a stripped TIFF - blocks whose height is the raster height. This is far less common, but occurs in some formats like DTED. > > A. > > 2015-08-23 11:40 GMT+02:00 Even Rouault <[email protected]>: > > Le dimanche 23 août 2015 11:28:21, Andrea Peri a écrit : > >> Hi Even, > >> thx for reply. > >> > >> So actually a tiff born to be used with vrt datasource be better if > >> you was with a tile=128x128 instead of tile=1024x1024 > >> > >> right ? > > > > I guess that should help in most cases, but almost due to the reduced > > tile size than the matching between TIFF and VRT block size. For > > example, if the VRT is read by an algorithm that processes line by line, > > a reduced tile size will cause less data to be read. > > Increasing GDAL_CACHEMAX can also be an alternative > > > >> A. > >> > >> 2015-08-23 10:51 GMT+02:00 Even Rouault <[email protected]>: > >> > Le dimanche 23 août 2015 07:43:03, Andrea Peri a écrit : > >> >> Hi, > >> >> I have a tiff tiled with tile size 1024 x 1024. > >> >> > >> >> When I try to build a vrt-datasource on it using the gdalbuildvrt. > >> >> I see the result vrt file report a > >> >> block of 128x128 instead of 1024x1024. > >> >> > >> >> I dont know if this is correct by the gdalbuildvrt oint of view > >> >> > >> >> Also I like to know if is preferrably to correct manually the vrt > >> >> result to report the right value 1024 > >> >> or is also acceptable to maintain the 128 size reported for the right > >> >> work of the gdal utilities in the vrt file. > >> > > >> > Andrea, > >> > > >> > the 128x128 block size is currently hardcoded in the VRT driver. We > >> > could imagine extending the VRT syntax to have user defined block > >> > size. > >> > > >> > Even > >> > > >> > -- > >> > Spatialys - Geospatial professional services > >> > http://www.spatialys.com > > > > -- > > Spatialys - Geospatial professional services > > http://www.spatialys.com -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
