[OSGeo-Discuss] OS Raster server advice?

[Tim Sutton]

Hi Sylvan

2008/10/17 Sylvan Ascent Inc. <sylvanascent at mail2web.net>:
> Hello everyone,
>
> We are looking at putting together a big, fast raster server for a Gis
> warehouse, and prefer open source. What would you use if you had to store
>>20TB data, serve any of it quickly to WMS or Google Earth, as well as being
> able to create any sort of output image in most any format/projection. I've
> used GDAL extensively in the past, but not sure it would be the best way to
> proceed, or how to store the data.

I have been serving up fairly large datasets using mapserver
(http://mapserver.gis.umn.edu/) by doing:

 - chop the dataset into multiple smaller images and save as
compressed tif (or uncompressed might offer better performance if
space is no concern)
 - generate internal tiles and pyramids
 - use gdaltindex to create an image catalogue
 - add the image catalogue to your mapfile
 - configure mapserver to provide the lmage as wms
 - run on a fast server

All these steps are pretty well explained in both the GDAL and
MapServer documentation if you care to take a look there for details.
For even better
performance you could probably employ tilecache (but at the expense of
more hard disk space required to store the tiles I guess). Others with
more knowledge feel free to point out better ways to do this, but this
works pretty well for me. Also note that pretty much everything above
can be automated with GDAL commandline tools and a few lines of bash.

>
> I recently saw Rasdaman is going open source, a possibility? Also that
> GlobeXplorer used PostGIS (but how?) We also want WCS, but I'm not exactly
> sure what that even means.

WCS = Web Coverage Service is described here :
http://en.wikipedia.org/wiki/Web_Coverage_Service

Have fun!

Regards


-- 
Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
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