[postgis-users] PostGIS Raster Performance

[Simon Greener]

Sunny etc,

I have summarised my experience with determining optimal tile sizes to ensure optimal
database/file access performance here: http://www.spatialdbadvisor.com/blog/175/tiling-very-large-rasters

Please let me know if it is of any use.

regards
Simon
On Mon, 31 Jan 2011 15:05:19 +1100, Simon Greener <simon at spatialdbadvisor.com> wrote:

> 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:
> www.spatialdbadvisor.com/files/TilingVeryLargeRasters.pdf
> 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.
>>>
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at postgis.refractions.net
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>
>>>
>>
>
>


-- 
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