[Gdal-dev] WCS Client Driver
Tom.Kralidis at ec.gc.ca
Wed Oct 4 14:18:47 EDT 2006
> -----Original Message-----
> From: Frank Warmerdam [mailto:warmerdam at pobox.com]
> Sent: 04 October, 2006 2:01 PM
> To: Kralidis,Tom [Burlington]
> Cc: gdal-dev; Bart van den Eijnden (OSGIS)
> Subject: Re: [Gdal-dev] WCS Client Driver
> Kralidis,Tom [Burlington] wrote:
> > Hi,
> > (jumping up and down -- good news!).
> > This will undoubtedly increase the usage of WCS servers.
> > Though I'm not a part of the PSC, I provide the following comments
> > (interleaved):
> >> The WCS coverage driver will read a service description file to
> >> establish the parameters it requires to make GetCoverage
> calls on a
> >> WCS server. If the the service description file lacks
> >> DescribeCoverage information for the coverage, the driver
> will invoke
> >> DescribeCoverage, and fill in the service description file on disk.
> > In terms of MapServer, this is a bit different than the other OWS
> > client approaches (i.e. the code is in MapServer itself for
> WMS, WFS client).
> > I would be interested in how this functionality will "roll up" to
> > MapServer and what the relationship is. Just want to make
> sure there
> > are little/no duplications.
> This is indeed quite different from the approach in MapServer
> for WFS and WMS client support. Mainly this different is
> because the client isn't using GDAL from MapServer, so I
> needed to implement a GDAL-only approach.
> So, in a sense there will be some duplication of mechanisms
> but I don't see it as easily avoidable.
> >> Specification Features
> >> ----------------------
> >> Version:
> >> o The driver will support WCS version 1.0.0.
> >> o The driver will support WCS version 1.1.0 based on
> current draft.
> >> (Phase 2)
> > I'm pretty sure 1.1.0 implements the owsCommon specification. It
> > would be valuable when implementing anything from owsCommon that it
> > can be reused in some way. I could see this being leveraged in
> > MapServer (even as a code copy/paste) for the logic.
> I'm not sure how easy sharing will be (other than as example code).
> BTW, what version(s) of WMS and WFS use owsCommon? It might
> make sense at some point to implement WFS and WMS client
> support in OGR and GDAL respectively, and some leverage of
> owsCommon might apply at that point.
OGC:WMS does not use it yet, but will (1.4.0?). OGC:WFS 1.1.0 uses
> > Frank: you may want to look at what we did for the
> OWSContext work for
> > binding to a WCS in a context doc.
> Could you provide a specific pointer for me, and what I
> should be looking for?
If you're an OGC member, an example is available at:
Else, here's an XML snippet of what a WCS Coverge binding would look
<Server service="OGC:WCS" version="1.0.0"
title="Boston Indexed Geotiff imagery">
<Title>MOD_Grid_L2g_2d Coverage Offering</Title>
<Abstract>MOD_Grid_L2g_2d Coverage Offering,
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