Hi, I suppose that Even means that with AUTO setting Mapserver is analyzing the min/max pixel values from inside the BBOX of each GetMap and then scales pixel values to 0-256 for the output. One totally black or white pixel within the BBOX can make the result from 64bit source very bad.
I would try to use LUT instead of SCALE http://www.mapserver.org/input/raster.html#special-processing-directives. -Jukka Rahkonen- -----Alkuperäinen viesti-----l Lähettäjä: [email protected] [mailto:[email protected]] Puolesta Andrea Peri Lähetetty: 4. elokuuta 2015 20:07 Vastaanottaja: Even Rouault Kopio: [email protected] Aihe: Re: [mapserver-users] processing scale=auto with float multibands rasters Hi Even, thx for response. Please can you help me to better understand the question ? My raster is effectively a 18000 x 24000 px image with tiles. it have a tile size of 1024 x 1024 produced from gdalwarp: gdalwarp -s_srs EPSG:32632 -t_srs EPSG:32632 -overwrite --config GDAL_CACHEMAX 1000 -wm 1000 -co TILED=YES -co COMPRESS=NONE -co BLOCKXSIZE=1024 -co BLOCKYSIZE=1024 -co BIGTIFF=YES -co SPARSE_OK=TRUE ....... and also have overviews from gdaladdo --config GDAL_CACHEMAX 1500 -ro -r average ..... 2 4 8 16 32 64 128 256 512 1024 If I understand correctly your info. The mapserver could search the min/max using only the first tile ? This mean that it more probably found always only 0 values or near 0 values beacuse these could be the values in the first tile. And so it return a white image because the min/max is always min=0/ max=0 (or something quite like this) I understand correct ? thx, A. 2015-08-04 16:01 GMT+02:00 Even Rouault <[email protected]>: > On Monday 03 August 2015 11:02:43 Andrea Peri wrote: >> Hi, >> I have a geotiff multibands with float64 values to serve with a wms >> mapserver service. >> >> With this kind of rasters, >> is affordable the directive >> >> PROCESSING "BANDS=4,3,2" >> PROCESSING "SCALE=AUTO" >> >> (the 4,3,2 are the red,green,blue channels) >> >> Infact it seem do nothing. >> >> Instead all work well if I set: >> >> PROCESSING "BANDS=4,3,2" >> PROCESSING "SCALE_1=0.01,0.2" >> PROCESSING "SCALE_2=0.01,0.2" >> PROCESSING "SCALE_3=0.01,0.2" >> >> where ii use the min=0.01 and max=0.2 But I like to have the exact >> values of min/max for every raster. > > Andrea, > > SCALE=AUTO should work but looking at the actual implementation I can > see it computes the min/max on the pixel values intersecting the > requested area, and not on the whole raster as I'd have expected. So > in a tiling context, it will likely not produce the expected result. > > Even > > -- > Spatialys - Geospatial professional services http://www.spatialys.com -- ----------------- Andrea Peri . . . . . . . . . qwerty àèìòù ----------------- _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
