I'm trying to calculate statistics for a raster layer using an overlaying polygon layer, I'm using SAGA "Grid Statistics for polygons" function, but it returns an error, sadly.. So in the sextante log it says :
Parameters Grids: No objects Files: "Y:/.../clipper_grassexport_0to11" loading: Y:/.../clipper_grassexport_0to11 Driver: Y:/.../clipper_grassexport_0to11/ Cells: x 44069, y 42309 Bands: 1 Transformation x' = 2635889.298915 + x * 100.001118 + y * 0.000000 Transformation y' = 5421705.687421 + x * 0.000000 + y * -100.000407 Module caused access violation! GDAL: Import Raster: Module caused access violation! error: executing module [GDAL: Import Raster] *** go... Load grid: C:\Users\...\AppData\Local\Temp\sextante\1368631882.798.sgrd... failed error: Grid file could not be opened. error: input file [C:\Users\...\AppData\Local\Temp\sextante\1368631882.798.sgrd] error: empty input list [GRIDS] Usage: Grid Statistics for Polygons -GRIDS <str> -POLYGONS <str> [-RESULT <str>] [-COUNT] [-MIN] [-MAX] [-RANGE] [-SUM] [-MEAN] [-VAR] [-STDDEV] [-QUANTILE <num>] -GRIDS:<str> Grids Grid list (input) -POLYGONS:<str> Polygons Shapes (input) -RESULT:<str> Statistics Shapes (optional output) -COUNT Number of Cells Boolean -MIN Minimum Boolean -MAX Maximum Boolean -RANGE Range Boolean -SUM Sum Boolean -MEAN Mean Boolean -VAR Variance Boolean -STDDEV Standard Deviation Boolean -QUANTILE:<num> Quantiles Integer Value Range: 0.000000 - 50.000000 error: executing module [Grid Statistics for Polygons]
I have tried to load my raster and vector layers into SAGA directly, but the raster layer wouldn't load, and same error appears - "Module caused access violation!"
Checked if SAGA is properly installed, and is 2.0.8 version (QGis 1.8.0)
Raster is an GEOTIFF exported from GRASS Tools in QGis in Byte format (Values 0-255), CRS's also match, I have run out of ideas, what could possibly be wrong?
It would be great to have some help! Thanks!
Update - June 17 2013
So to sum it all up - with a large dataset it still gives an error, but if I want to divide the raster in say 4 smaller parts, raster Clipper Tool does it for ages and freezes with an approximate filesize of 100-140 MB, that means I have found no solution yet, that does the job efficiently.