Peter, Actually, I should have added that I think a following stage should be for you to prepare a formal detailed RFC proposal for voting on by the PSC rather than just throwing a patch at us since this is an API change.
Best regards, Frank On Tue, Apr 23, 2013 at 3:16 PM, Frank Warmerdam <[email protected]>wrote: > > > > 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 > -- ---------------------------------------+-------------------------------------- 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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