Hi, Read and tried http://docs.oam.osgeo.org/storage/creating.html. It's really nice to have 5 megs of geotiff instead of 700 :)
Serving tiffs with MapServer: http://latlon.org/maxi?zoom=14&lat=56.33918&lon=30.5554&layers=0000000000000FF0000FBT Still, there are some things I would like to clear / discuss. 1) gdaladdo final.tif 2 4 8 16 32 64 128 256 makes not beautiful overviews. If I add -r average, some artifacts start appearing, like the vertical stripes on the link above. Any good ways to fix that? 2) why is EPSG:4326 used for saving images? Images look distorted in it when they're not on equator. Isn't it better to use EPSG:3857 mercator, which is in fact used everywhere to display imagery and map data? Also, a far as I can see, jpeg compression has quantization matrix that is kinda optimized for human eye, letting more higher frequences horizontally than vertically. And after that we crop off another portion of high frequency information on vertical axis. 3) JPEG compression artifacts. Black field outside makes outmost blocks appear darker and be "dirty": http://latlon.org/maxi?zoom=18&lat=56.32465&lon=30.61984&layers=0000000000000FF0000FBT This can be avoided, as far as I can see, in two ways: a) easier one, on compression, if we fill NODATA region inside these blocks not with black, but with bilinear average of other data inside block, there will be no black blocks. b) harder one, make custom jpeg decompressor that will take exact value for nodata region into account and try to restore values for DATA region (not sure if it's really possible). Same about compressing overviews. Probably nearblack can be patched to fill regions not with black but with any kind of average, as quick-and-dirty solution? 4) any beautiful programs to manage mosaics (chop off clouds, selecting which image goes over which...) around? ;) -- Darafei "Komяpa" Praliaskouski OSM BY Team - http://openstreetmap.by/ xmpp:m...@komzpa.net mailto:m...@komzpa.net _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
