On Thursday 26 May 2016 13:26:38 Jukka Rahkonen wrote: > Daniel Morissette <dmorissette <at> mapgears.com> writes: > > On 2016-05-26 8:40 AM, Jukka Rahkonen wrote: > > > Hi, > > > > > > Any thoughts about alternatives to implement the feature request from > > > https://trac.osgeo.org/gdal/ticket/5762? > > > > > > What I dream of is to be able to utilize all the nice on-the-fly tweaks > > > that can be done with VRT at similar speed that Mapserver is reaching > > > with > tileindex. > > > That would be a nice enhancement. As usual I guess we need a champion > > and/or some funding to make this happen. > > > > I came across a similar use case not long ago and realized that to get > > top performance at all zoom levels we'd also need the ability to > > associate overviews with the VRT. I didn't check if creating external > > overviews with gdaladdo would work for a VRT already. Maybe it does? > > It does and is even documented in > http://www.gdal.org/gdal_vrttut.html#gdal_vrttut_overviews. > > VRT supports one overview, but that can itself be a VRT, which in turn can > point to next VRT overview and so on.
Actually, this is not true (although I might have in the past say so). The doc currently states : """ Overview: This optional element describes one overview level for the band. It should have a child SourceFilename and SourceBand element. The SourceFilename may have a relativeToVRT boolean attribute. Multiple elements may be used to describe multiple overviews. """ and I've verified it works (at least they are reported by gdalinfo) Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
