[Gdal-dev] WCS Client Driver

[Frank Warmerdam]

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.

Tom,

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.

> 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?

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org