[gdal-dev] Warping MrSid Images

[Dan Greve]

Greetings,

I'm having an issue with a MrSid dataset.  Performance seems to be dreadfully slow reprojecting data from this 14336 pix by 14336 pix 8bit, 3 band RGB, UTM rotated image with 8 overviews. Whether I warp the image into a  512 pix x 428 pix geotiff or a 15620 pix x 13102 pix geotiff, (EPSG:4326) both warp operations take over 5 minutes. (5:30 for the small image, 7:15 for the large which required 600 megabyte of disk output). 

Might there be a better way of creating a VRT, grabbing one of the overview bands, and using this virtual "overview" dataset in the warp operation.  Strangely enough, if I translate the source into a GeoTiff, and create 8 explicit overviews, the 512 pix x 428 pix warp operation takes about 30 seconds.

-- Dan Greve
-- Software Engineer
-- Northrop Grumman Integrated Systems

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