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I have a whole series of GeoTiff tiles, each one about 250mb in size, in total just over 90gb. I want to be able to display these as a wms into QGIS to 20+ GIS users and in the end make them into a tile cache. My problem is that I don't have enough server space to stick the GeoTiff tiles on to in their current state, so they are living on an external hard-drive. My server contains GeoServer and I've also got access to MapServer on the same server but I'm less fluent its configuration than I am with GeoServer.

Is there a way that I could reduce the size per GeoTiff to make them more manageable or should I convert them into another file tile, png/jpeg2000 for example?

Has anyone else any experience of such large GeoTiff sizes and what did you do with them?

Oh and I'd like to do this entirely with OpenSource (if possible).

Med

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I think the tile cache (which you mentioned as your ultimate goal) is really the answer to your question of how to make big amounts of GeoTiff usable. –  underdark Jul 29 '12 at 11:09

2 Answers 2

up vote 7 down vote accepted

If you can accept some quality degradation in the image, you may try out something like the following, using the GDAL utilities:

gdal_translate -co "TILED=YES" -co "COMPRESS=JPEG" -co "PHOTOMETRIC=YCBCR" input.tiff output.tiff

gdaladdo -r average --config COMPRESS_OVERVIEW JPEG --config PHOTOMETRIC_OVERVIEW YCBCR 2 4 8 16 output.tiff

The above should suit imagery, if the TIFFs are scientific data instead (e.g., elevation, salinity, temperature, and so on) you might want to look into LZW compression instead.

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Thanks for the above GDAL heads up, I'll check this out tomoz and report back on my findings. The rasters are simply aerial photographs, so nothing scientific about them. Ta –  geosmiles Jul 29 '12 at 18:48
    
Thanks Andrea your GDAL points worked a treat. I've got a more healthy file size of 2.3gb for all my tifs now instead of the 90gb. Quality seems to be as good as the originals and QGIS, GEOSERVER and my server are all very happy. Thanks again –  geosmiles Jul 30 '12 at 18:06

And be sure to use -co "TILED=YES" to be able to compress huge files with jpeg, since jpeg only allows small images. (We speak about some thousand pixels per dimension...)

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