Ticket #2076 (new defect)
[PATCH] gdalwarp doesn't use overviews
|Reported by:||crschmidt||Owned by:||warmerdam|
It appears that gdalwarp does not take advantage of overviews, always choosing to read the entire source data when doing warping.
For the WMS driver, this means that warping any section of the map results in it reading the entire dataset at the lowest level from the dataset. In the case of OAM, this actually results in entirely black blocks being read for most areas, because the data isn't high enough resolution to actually have any pixels displayed per tile/block.
The end result is that gdalwarp against a WMS service essentially doesn't work. (Instead, one must project the coordinates, use gdal_translate, then gdalwarp the resulting image.)
To reproduce, do something like:
233978.513603 899703.853477 237679.486397 902022.146523 -ts 803 503 -t_srs EPSG:2805 gdal_wms.xml foo.jpg