On Friday 16 Aug 2013 18:08:53 Andranik Hayrapetyan wrote: > Good day, > > I would like to understand how GRASS loads raster images into memory to > perform calculations on them. > Does it load the entire image into memory and only then do the calculation > on them, or it loads image into memory by portions sequentially?
As far as I know, there are no functions in the C-API of GRASS to load the whole raster map into the memory... And in general is not a good idea... You can read/write a raster row by row with: http://grass.osgeo.org/programming7/raster_2get__row_8c.html http://grass.osgeo.org/programming7/raster_2put__row_8c.html Then exist the Raster RowIO that provide a row cache to avoid to read several time always the same row from the hard disk. http://grass.osgeo.org/programming7/rowio_2setup_8c.html And last but not least the Raster Segment, that split the map not by row but in several tiles and provide a tile cache, allowing to open a map in read-write mode. http://grass.osgeo.org/programming7/structSEGMENT.html http://grass.osgeo.org/programming7/segment_2local__proto_8h.html http://grass.osgeo.org/programming7/segment_2get_8c.html http://grass.osgeo.org/programming7/segment_2put_8c.html Regards Pietro _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
