[OSGeo-Discuss] RE: OGC WPS and Amazon SQS
Dr. Markus Lupp
lupp at lat-lon.de
Wed Feb 27 21:04:21 EST 2008
deegree has a WPS implementation (although by now it supports only WPS
v. 0.4.0). We plan to publish an easy-to-install WPS Demo Release for
deegree 2.2, coming in June (1st Release Candidate in April).
Randy George schrieb:
> I noticed OGC finalized the WPS spec:
> 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
> 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:
> 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
> 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:
> Discuss mailing list
> Discuss at lists.osgeo.org
Dr. Markus Lupp
l a t / l o n GmbH
phone +62 (0)81 339 431666
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