[postgis-users] PostGIS Raster Performance

Simon Greener simon at spatialdbadvisor.com
Sun Jan 30 20:05:19 PST 2011

Is it possible to get some sort of idea about how the raster data is being organised
and what scales is it being asked to support?

In all my experience the critical factor with raster data for display rendering
is the issue of the size of the storage tile relative to the average display window.
This was investigated back in the 1980s quite well by Peter Lamb of the CSIRO Division of
Information Technology in Australia: his paper "Tiling Very Large Rasters" is worth
reading. I have put a draft version of the report on my website:
for you to peruse. I used a paper Peter produced to design the original www.whitepages.com.au
raster (tiled) database.
On Sun, 30 Jan 2011 13:24:34 +1100, Sunny Teo <spatialsunny at gmail.com> wrote:

> Hi Regina,
> Thanks for the lead on this.
> It opens up the light and the room for discussion. Well, as far as I know,
> Oracle Georaster is not good for serving purpose and on top of it, that
> takes awful amount of time to load the data into Oracle. I assume that its
> not the case with PG Raster.
> The other issue is, even if one dont want to do store the multiband (say 8
> band) imagery into the PG Raster for the Speed issue, can we target to link
> up the Cache into this? If GWC or Tile Cache jpg/png tiles can be kept here
> and then publish... it will be nice. Again, the issue will be speed ... or
> some may argue the fact the it defeats the purpose of Cache which is suppose
> to be non "ram" required serving.
> my only wish, that one day we should be able to easily load the images into
> PG Raster and publish into a web application and get a performance/speed as
> good as any image servers.
> btw, it was a news to me that GeoServer dont support PG Raster yet... I hope
> they are working on it now...
> Thank you;
> Sunny
> On Sun, Jan 30, 2011 at 6:30 AM, Paragon Corporation <lr at pcorp.us> wrote:
>>  Sunny,
>> Good question.  I suspect it will be worse at least at the moment (just as
>> PostGIS was worse when it first came out than reading from shapefile).  How
>> much worse I'm not sure.  If you try and see speed issues, we can tackle
>> them, but it hasn't really been our main focus.
>>  I suspect no one has tested it extensively as far as dishing out large
>> datasets.  The primary focus of PostGIS Raster is for analysis and then
>> secondary is the rendering.  That is not to say it will work badly or we
>> don't care about rendering speed, just that the GDAL drivers etc. needed by
>> Mapserver probably still have a few wrinkles which would make it suboptimal
>> for that kind of work.  The more people use it and find issues, the faster
>> issues will be addressed since we would have data points to go by.
>> As far as GeoServer goes, I recall reading a thread where Chris Holmes said
>> he would work on a PostGIS Raster support for GeoServer, but not sure where
>> that is down the pipe, but to my knowledge, GeoServer does not YET support
>> PostGIS raster.
>> Hope that helps,
>> Regina
>>  ------------------------------
>> *From:* postgis-users-bounces at postgis.refractions.net [mailto:
>> postgis-users-bounces at postgis.refractions.net] *On Behalf Of *Sunny Teo
>> *Sent:* Saturday, January 29, 2011 3:44 AM
>> *To:* postgis-users at postgis.refractions.net
>> *Subject:* [postgis-users] PostGIS Raster Performance
>> List,
>> Can anyone comment on the "Performance" of the PostGIS Rater or WKTRaster ?
>> If you were to serve this onto a web application, how effective are they?
>> Well, I'm talking of very large datasets like 10GB each and 100 of them. How
>> does it compare with serving the images as files directly.. from a GeoTIFF,
>> ECW, Sid, etc. (obviously using Geoserver/Mapserver or some specialized
>> image serving solution)
>> Been searching all over the web for the answers, but no luck.
>> Hope to get some insights from the users.
>> Thank you;
>> Sunny.
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SpatialDB Advice and Design, Solutions Architecture and Programming,
Oracle Database 10g Administrator Certified Associate; Oracle Database 10g SQL Certified Professional
Oracle Spatial, SQL Server, PostGIS, MySQL, ArcSDE, Manifold GIS, FME, Radius Topology and Studio Specialist.
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