Hi All, Sam and I have prepared an RFC for our proposal for improving raster attribute table (RAT) support and put it on the trac.
http://trac.osgeo.org/gdal/wiki/rfc40_enhanced_rat_support We'd be keen to here feedback on our proposal. Best wishes, Pete **************************************************** * Dr Pete Bunting * Senior Lecturer in Remote Sensing * Institute of Geography and Earth Sciences * Aberystwyth University * Aberystwyth * Ceredigion * SY23 3DB * UK * * Ph: +44 (0) 1970 622615 * Mob: +44 (0) 7917 842743 * NZ Ph: +64 (0) 4 280 7430 * Email: [email protected] **************************************************** On 24 Apr 2013, at 11:03, Peter Bunting <[email protected]> wrote: > 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 > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev
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