[postgis-users] Raster data

[Chris G. Nicholas]

You can access our entire archive as a single seamless image layer, and our mean response time in just under a second for 400x400 jpegs, delivered in a user-defined projection...

(but then again our stuff isn't really in a state, technically or legally, where one might just ftp and unpack a .gz, run "configure; make; make install" either :-)

We should take this discussion off-line, but I guess my short answer is: 

if the content you want to use is a few hundred gigs after MrSid or Jpeg2000 compression, just use flat files and a mapserver of choice to serve it up: (Minn Map Server, ArcIMS, Mapguide, GeoMedia, etc)  Use PostGIS to keep track of it all.

after that, consider using GlobeXplorer... :-)

Chris Nicholas

-----Original Message-----
From:	Christoph Spoerri [mailto:spoerri at duke.edu]
Sent:	Mon 3/10/2003 8:39 AM
To:	PostGIS Users Discussion
Cc:	
Subject:	Re: [postgis-users] Raster data
Chris,

Could you provide me with some more details on your raster setup? It sounds as 
you have a good solution to manage such large datasets. Whats the largest 
raster you are serving up?

Regarding the server vs. client issues: I was thinking that the 
compression/decompression may occur on the client (save bandwidth and 
increase performance on server). The same should be the case for 
reprojection. Mosaicking would be done on the server. In addition the server 
would create pyramids in order to improve the performance when rasters are 
only used for display. 

While a db system does not have a significant advantage for small rasters (10 
- 100 Mb?), I believe that performance improves with larger rasters, since 
the db can index individual tiles of the entire raster and its pyramids.

In ArcSDE I'm serving up a 300 GB, seamless raster which takes between 5 - 20 
seconds to display over the net independent of scale or extend.

Of course I'm open to any suggestions, opinions or comments.

Christoph

On Monday 10 March 2003 10:59 am, Chris G. Nicholas wrote:
> What were you looking for? We have 200+ terabytes of raster content
> available as an OpenGIS WMS, all of which we index/manipulate using a
> spatial db. We use transactions to store, move, etc the raster files, but
> we certainly don't store it all *in* the db.
>
> For example - where do you want decompression of MrSid and/or Jpeg2000
> imagery to occur? Where do you want reprojection to occur? How would you
> control mosaicing? In the db or in the client?
>
> Chris Nicholas
> GlobeXplorer
>
> -----Original Message-----
> From:	Christoph Spoerri [mailto:spoerri at duke.edu]
> Sent:	Mon 3/10/2003 6:51 AM
> To:	PostGIS Users Discussion
> Cc:
> Subject:	[postgis-users] Raster data
> Hi,
>
> I'm new to PostGIS and this list so I'm not sure if this questions came
> already up.
>
> I was wondering if there are any plans on incorporating raster data into
> PostGIS? I had some very good results with using raster data in ArcSDE and
> would like to see a similar feature in PostGIS. Does anybody work on this?
> Is there some need for it? If not, what are the arguments against it?
>
> Thanks,
> Christoph


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