search

qissue-bot / QGIS

QGIS is a free, open source, cross platform (lin/win/mac) geographical information system (GIS)
http://qgis.org
GNU General Public License v2.0
0 stars 0 forks source link

Pyramids are not build if tifw contains rotations #1709

Open qissue-bot opened 5 years ago

qissue-bot commented 5 years ago

Author Name: Maxim Dubinin (Maxim Dubinin) Original Redmine Issue: 1722, https://issues.qgis.org/issues/1722

If tfw file contains rotations terms, pyramids are not build with the message: "Not supported on this type of raster".

Example attached, see lines 2 and 3, not equal to 0. Replicated in 1.0.2 and 1.2-trunk

qissue-bot commented 5 years ago

Original Redmine Comment Author Name: ersts - (ersts -) Original Date: 2009-07-27T18:33:16.000Z

This is because the image is warped when it is loaded and considered a 'warped virtual dataset'. The image being drawn is not the original base image, though we do still have a pointer to that base image.

It seems like pyramids could be build for the based image, and then reloaded and rewarped again, but I need to check with the GDAL folks to see if pyramids are supported at all with virtual datasets.

qissue-bot commented 5 years ago

Original Redmine Comment Author Name: Maxim Dubinin (Maxim Dubinin) Original Date: 2009-07-27T18:44:06.000Z

I think the pyramids should be built for the base raster.

qissue-bot commented 5 years ago

Original Redmine Comment Author Name: Frank Warmerdam - (Frank Warmerdam -) Original Date: 2009-07-27T18:51:01.000Z

Overviews can actually be built on vrt warped images however that doesn't work in the QGIS case where the warped VRT is actually just temporary - not saved to disk.

We could also build overviews on the underlying image however at this time the GDAL warp api underlying warped VRTs does not take advantage of overviews.

qissue-bot commented 5 years ago

Original Redmine Comment Author Name: ersts - (ersts -) Original Date: 2009-07-27T19:02:13.000Z

Replying to [comment:5 warmerdam]:

We could also build overviews on the underlying image however at this time the GDAL warp api underlying warped VRTs does not take advantage of overviews.

Thanks Frank, that was the nugget I was looking for. So for now I guess we will just keep the ticket open and watch the following ticket

http://trac.osgeo.org/gdal/ticket/2076