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I am trying to speed up rendering of OS raster map tiles in QGIS.

The tiles are 1:10k Tiffs - about 130 of them.

When I attempt to build the VRT it says complete, then it shows up an error message:

Warning 6: gdalbuildvrt does not support rotated geo transforms.

The only settings I had on whilst creating the VRT were: resolution - highest Add to canvas after finishing

As you can see from the image some of the tiles were successful. I didn't have a problem with creating a VRT for 1:50k or 1:250k map tiles.

Any suggestions or advice on speeding up rendering of OS map tiles (such as pyramids) would be much appreciated.


share|improve this question
do your tiffs have tfw files with rotation values in them? – Mapperz Dec 3 '12 at 16:57
We always converted tiffs to png - purely for small files and faster displays. Setting a Layer with Scale visibility <10,0001 also was more efficient. – Mapperz Dec 3 '12 at 16:59
This is OS StreetView? Anyway, it might be worth checking that each TIFF has its own world file (in the same directory). N – nhopton Dec 3 '12 at 18:00
+1 for nhopton - For some reason OS likes to bundle its world files into a separate directory to the rasters, if you get a world file at all. I have had to download them separately on occasion. – MappaGnosis Dec 3 '12 at 18:19

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