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...as opposed to keeping the rasters as locally stored GEOTIFFs?

I have a large project that will require making available approximetely 50,000, 10mb GEOTIFFs as WMS to an OpenLayers based web map. Only 1 WMS will be displayed at any given time so performance is a non-issue. Considering MapServer and GeoServer for this application.

I would like to know what are the advantages and disadvantages of storing this type of data. Will updating a PostGIS database when the raster data changes be more difficult, rather than replacing a single (or series of) raster files. WMS load times drastically improved with PostGIS?

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up vote 3 down vote accepted

If all you're doing is passing rasters to end users with WMS, there is no reason to use PostGIS raster. If you need to do analysis (and more than a simple summary stats), then you may want to consider loading the rasters into PostGIS. Currently, in-db rasters are faster than out-db.

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Can you expand.on in-db and out-db, what they mean and why one is slower then the other. –  Michael Markieta Aug 28 '12 at 13:11
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in-db is where the source raster (tile) is stored in PostgreSQL. out-db only stores metadata describing the source raster in PostgreSQL and any functions in PostGIS will call the source raster files as needed. In my testing, out-db is slower than in-db. As to why out-db is slower, my suspicion is that PostgreSQL is able to cache the in-db data in its shared buffers while out-db requires calling the source file every time. –  dustymugs Aug 31 '12 at 17:12
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From general reading of MapServer and GeoServer comparisons online, I found the consensus to be that MapServer was quicker for serving rasters. I have a setup similar to what you describe for providing rasters (rasters in a folder) as a WMS using MapServer and it is extremely fast.

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