[gdal-dev] ReadAsArray

[Even Rouault]

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