On Tue, Apr 23, 2013 at 1:57 PM, Peter Bunting <[email protected]> wrote:
> Hi All, > > We were wondering if there is any interest in the GDAL community for > improving the Raster Attribute Implementation? Within our group of > collaborators we have been representing image segmentations as clump files > often large attribute tables containing millions of rows and numerous > columns of data used for classification. We are finding the current > approach that reads a single value at a time with the whole attribute table > in memory to be quite poor performance wise and resource (i.e., memory) > hungry. > Peter, You do seem to be pushing raster attribute tables well beyond the expected use cases. > > We would like to propose a new implementation that allows reading and > writing of whole chunks of a single column within the attribute table more > like RasterIO. > > If we were to create a patch, would the GDAL community be receptive to > this? We were thinking this would be incorporated within the interface > changes in GDAL 2.0. > I would be receptive to additional read (and perhaps write) methods for chunks of the attribute table at a time if it can be done with a minimum of distruption of the existing api. > It has been muted that OGR might be merged into GDAL in version 2.0 if > this were to occurred how would attribute tables be dealt with and are the > changes we proposing something that needs to be considered in that wider > context also? > I had not been contemplating treating raster attribute tables as OGR layers. I must confess that I'm still not certain that pushing raster attribute tables to be very large is a good idea. Best regards, ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [email protected] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Software Developer
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