[OSGeo-Discuss] RE: OGC WPS and Amazon SQS

[Jachym Cepicky]

THere is also pywps project

http://pywps.wald.intevation.org

with direct support for grass gis

jachym

Randy George píše v St 27. 02. 2008 v 09:11 -0700:
> I noticed OGC finalized the WPS spec:
> http://www.opengeospatial.org/pressroom/pressreleases/843
> 
>  
> 
> Does anyone know of projects working on WPS implementations?
> 
>  
> 
> The goal of WPS is apparently to provide a consistent framework for
> interchangeable service process algorithms that can potentially be
> chained together into answers to higher level questions than the
> typical ‘what’, ‘when’, and ‘where.’ Dealing with ‘why’, ‘how much’,
> and ‘what if’ modeling usually requires a process pipeline for
> convolutions, boolean band operations, and summary pixel calculations,
> all of which are cpu cycle intense, especially for large imagery sets.
> In fact cpu usage issues would make the usual service approach
> prohibitive.  Even the little I have worked on JAI pipelines shows me
> the futility of a one cpu to many service requests approach for WPS.
> 
>  
> 
> However, looking at the AWS Simple Queue Service, SQS
> http://www.amazon.com/Simple-Queue-Service-home-page/b/ref=sc_fe_l_2?ie=UTF8&node=13584001&no=3435361&me=A36L942TSJ2AJA, some interesting possibilities come to mind.
> 
> Locking message queues with AMI instance pools is essentially a poor
> man’s supercomputer. It would be interesting to look at harnessing the
> utility computing concept with instance pools available for each stage
> in a process pipeline connected using the asynchronous SQS service.
> This is a more or less controlled ‘distributed computing model’
> applied to WPS. 
> 
> Ref here for some examples of existing distributed computing projects:
> http://distributedcomputing.info/projects.html 
> 
>  
> 
> Here are a couple possible approaches to a WPS service model that
> might overcome the cpu bottle neck:
> 
> 1)     Sequential SQS pipeline with dedicated instance for each
> process node - this would work best for operations amenable to a
> streaming pipeline – Boolean band operations or pixel summary
> operations for instance 
> 
>  
> 
> 2)     Distributed computing model with a chunk server feeding a
> pipeline and an array pool of instances processing the chunks coming
> down the SQS queue – this would be better suited to tiled operations 
> 
>  
> 
> WPS is great when someone else provides the service. I imagine it
> would be very interesting to the academic scientific world and
> government groups tasked with providing access to all the myriad
> imagery coming off space sensor platforms. 
> 
>  
> 
> Just thinking out loud.   More thoughts here:
>  http://www.cadmaps.com/gisblog/?p=28
> 
>  
> 
> randy
> 
>  
> 
> 
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-- 
Jachym Cepicky
e-mail: jachym.cepicky gmail com
URL: http://les-ejk.cz
GPG: http://www.les-ejk.cz/pgp/jachym_cepicky-gpg.pub
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