Le vendredi 03 avril 2015 12:46:48, Yuta Sato a écrit : > Dear Even Rouault: > > Thank you very much. > What about setting these parameters "used with .ReadAsArray()", though I > did not know their meanings? > buf_xsize=None, buf_ysize=None, buf_obj=None
(Please keep the list CC'ed) buf_xsize and buf_ysize are the equivalents of nBufXSize and nBufYSize in GDALRasterBand::RasterIO() http://gdal.org/classGDALRasterBand.html#a75d4af97b3436a4e79d9759eedf89af4 i.e. to do downsampling or upsampling of original data. buf_obj can be used to "recycle" an existing numpy array of the appropriate size instead of allocating a new one. > > > On Fri, Apr 3, 2015 at 7:43 PM, Even Rouault <[email protected]> > > wrote: > > Le vendredi 03 avril 2015 12:22:00, Yuta Sato a écrit : > > > Dear Respected GDAL Developers and Users: > > > > > > What parameters should I set beforehand in order to accelerate the > > > > reading > > > > > of a GeoTiff file? > > > > > > I am using as follows: > > > > > > data = src_dataset.GetRasterBand(1).ReadAsArray(xoff,yoff,xsize,ysize) > > > > > > Does setting the following parameters accelerate? > > > > > > GDAL_CACHEMAX, GDAL_SWATH_SIZE > > > > > > I'm using gdal python. > > > > Yuta, > > > > Increasing GDAL_CACHEMAX might accelerate in case of repeated reads on > > windows > > that are identical or overlapping already read windows. Or if the way you > > read > > the raster doesn't follow its block shape : for example if the raster is > > organized by lines/strips and you read by square blocks, or the reverse > > situation. > > > > GDAL_SWATH_SIZE is only used by CreateCopy(). > > > > Even > > > > -- > > 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
