[mapserver-users] Image quality
I am having issues with the output image quality of MapServer. I have a mapserver set up as a wms server up high res orthophoto images. The images are in tiled geotiff format with JPEG / YCBCR compression with internal gaussen overviews and referenced using a tile index in the mapfile with the PROCESSING RESAMPLE=BILINEAR directive. Mapserver 5.6.7 is set up using AGG with imagemode RGBA. I have noticed that the images generated have aliasing in areas of high contrast when viewing at various scales (full res seems fine). What is the optimal setup to reduce this effect? Regards ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Image Quality - Image Preprocessing
Hi Travis, >From a purely subjective standpoint, I feel that the bilinear resampling method works the best with aerial photo data. You can test this using gdalwarp: gdalwarp -ts -r But before you resample all your data, you might try adding the following processing directive to your imagery layer: PROCESSING "RESAMPLE=BILINEAR" You might find that this improves things enough. Roger -- On Wed, Mar 4, 2009 at 6:54 AM, Travis Kirstine wrote: > We are running mapserver connected to a tilecache delivering high > resolution orthophoto to a google maps. The problem I am having is > that we preprocess all our imagery using reduced resolutions at higher > scales and full resolution at lower scales. In the past we have used > gdal_merge with - ps 10 10 to merge tile into larger overalls and > downsampling the resolution but we have found that the image quality > was not adequate. I have been experimenting with gdalwarp using the > different resampling methods with varied results. Is there any > consensus on which resampling method provided with gdal provide the > optimal results (from a viewing perspective) when downsampling imagery > data? > > -- > Travis K. > > Toronto, Canada > > "She knows there's no success like failure > And that failure's no success at all." > -Bob Dylan- > > ___ > mapserver-users mailing list > mapserver-users@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/mapserver-users > ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
[mapserver-users] Image Quality - Image Preprocessing
We are running mapserver connected to a tilecache delivering high resolution orthophoto to a google maps. The problem I am having is that we preprocess all our imagery using reduced resolutions at higher scales and full resolution at lower scales. In the past we have used gdal_merge with - ps 10 10 to merge tile into larger overalls and downsampling the resolution but we have found that the image quality was not adequate. I have been experimenting with gdalwarp using the different resampling methods with varied results. Is there any consensus on which resampling method provided with gdal provide the optimal results (from a viewing perspective) when downsampling imagery data? -- Travis K. Toronto, Canada "She knows there's no success like failure And that failure's no success at all." -Bob Dylan- ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
