Ed McNierney wrote:
Your overviews can make things considerably worse.
Folks, Ed has hit on a dirty little secret of overviews here. Because of the way they are stored in TIFF files and the way libtiff and GDAL scan for their availability, opening a TIFF file with overviews is presumably substantially more expensive than opening a file without them. The TIFF directories will tend to be distributed through the file meaning quite a bit of seeking to get them all, and a standard GDALOpen will scan for them all. I don't want to discourage use of internal overviews. They are great from many angles. But when in use, it is still important to avoid having to touch too many files. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [EMAIL PROTECTED] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | President OSGeo, http://osgeo.org
