[OSGeo-Discuss] Raster data on RDBMS

Sylvan Ascent Inc. sylvanascent at mail2web.net
Wed Oct 29 09:14:51 PDT 2008


Hi Frank,
I'm not sure I completely agree about your apples/oranges, here's why:
 
We are in the process of putting together a big raster server, so I'm evaluating the best way to proceed. I'm quite familiar with putting raster tiles in a database, did that way back in the last century. I've decided to use Geoserver, since we need (want)  WFS-T and WCS, and the latest speed race between MapServer and GeoServer seems to be a tie more or less.
 
As I see it we have several options:
 
1) Put the big original raster images in back of Geoserver, access using their Mosaic and the GDAL based ImageIO-ext.
Advantage - easy, but kind of slow.
 
2) Take the originals and build a file-based pyramid
Advantage - faster, but a lot of work, plus duplication and tricky to keep updated as new data comes in.
 
3) Take the originals and build a PostGIS based pyramid.
Likely, about the same as 3 in speed and work and duplication.
 
4) Do 1, but put a pyramiding tileserver in front. It builds the pyrimid in 2 and 3 over time, and is likely the fastest if you hit the cache, and is no harder to do than #1.
 
I think, that since the goal of all this storage of pyramids and the like is just to get speed, that they aren't apples/oranges, but apples apples, since they are both pyramid schemes, just in different places, either in front, or in back of the server. 
 
Roger Bedell, President Sylvan Ascent Inc.
800-362-8971
+34 626 855 662
roger at sylvanascent.com <mailto:roger at sylvanascent.com> 
www.sylvanascent.com <http://www.sylvanascent.com/> 
www.topodepot.com <http://www.topodepot.com/> 

________________________________

From: discuss-bounces at lists.osgeo.org on behalf of Frank Warmerdam
Sent: Wed 10/29/2008 10:43 AM
To: OSGeo Discussions
Subject: Re: [OSGeo-Discuss] Raster data on RDBMS



Sylvan Ascent Inc. wrote:
> Mike and Ivan,
>
> I'd like to see them also compared to a caching solution, like GeoWebCache,
> or TileCache. These effectively create a file-based "database" of little
> bitty tiles at certain resolutions, kind of like a tile pyrimid that is
> created gradually over time as the image data is accessed.
>
> One would think the file-based cache system would be faster than a similar
> database solution, with the database solution giving no real benefits that I
> can see.

Roger,

While it might be educational to compare to a tilecache solution it is really
comparing apples and oranges.

Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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