Hi, 1) I am using average and our users have not complaint. But it is simple to test, you can create external overviews with -ro switch and try all the alternatives within on hour or faster. It will be nice to read about your experience. Take some timings too.
2) Jpeg in tiff suits pretty well for Mapserver, both for the images and overviews. 3) Never heard about such processing directives, need to test some day. -Jukka Rahkonen- ________________________________ Lähettäjä: mapserver-users-boun...@lists.osgeo.org [mailto:mapserver-users-boun...@lists.osgeo.org] Puolesta Mark Volz Lähetetty: 29. toukokuuta 2012 17:18 Vastaanottaja: mapserver-users@lists.osgeo.org Aihe: [mapserver-users] optimize raster for mapserver - gdal geoTIFF source Hello, I added a GeoTIFF to one of my .map files. When zoomed in the image appears fine. When I zoom out the image appears grainy, especially when looking at dirt fields. I assume the problem is that I built the overviews with the wrong resampling method when I built overviews with gdaladdo. Question 1) Does anyone have any recommendations for resampling air photos when I create an image using gdal? {nearest (default),average,gauss,cubic,average_mp,average_magphase,mode} Question 2) I am using a compressed geoTIFF with built in overviews. I am happy with this format as the file size is small, and the speed is fast. I am wondering if this is format for having a fast raster while keeping a relatively small file. Does anyone else have any other suggestions? Question 3) I have seen several Mapserver snippets of code concerning GDAL_FORCE_CACHING and GDAL_ONE_BIGREAD. If I am not reprojecting my imagery which processing directive(s) would be better for a compressed GeoTIFF with overviews? LAYER ... PROCESSING "GDAL_FORCE_CACHING = YES" Or: PROCESSING "GDAL_ONE_BIGREAD = YES" ... END # Air Photo Layer Thank You Mark Volz GIS Specialist
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