Thanks Frank, Sam and I will prepare a RFC and pass it around. Should we post it to the mailing list or add directly to the trac?
Best wishes, Pete On 24 Apr 2013, at 10:17, Frank Warmerdam <[email protected]> wrote: > 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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