Radim, I gather the problem is that GDAL cannot tell whether saved statistics in metadata are exact or not, right? I don't have any real plan to resolve this unfortunately. I ticket might be prudent.
Best regards, Frank On Thu, Oct 11, 2012 at 8:39 AM, Radim Blazek <radim.bla...@gmail.com>wrote: > GDALGetRasterStatistics API doc: > "Returns the minimum, maximum, mean and standard deviation of all > pixel values in this band. If approximate statistics are sufficient, > the bApproxOK flag can be set to true in which case overviews, or a > subset of image tiles may be used in computing the statistics. > If bForce is FALSE results will only be returned if it can be done > quickly (ie. without scanning the data). If bForce is FALSE and > results cannot be returned efficiently, the method will return > CE_Warning but no warning will have been issued. This is a > non-standard use of the CE_Warning return value to indicate "nothing > done"." > > > My understanding is that if it is called with bApproxOK=false and > bForce=false and exact statistics (from all raster pixels) are not > available/cached, it should return CE_Warning. Instead, it is giving > estimated (from sample) cached statistics and it returns CE_None. > > Is it expected? If it is, how can I test if exact statistics (from all > raster pixels) are available/cached (to avoid > GDALComputeRasterStatistics() if not necessary). Also, the meaning of > both params should be probably better described in doc. > > Radim > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Software Developer
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