[gdal-dev] WCS driver

[Ari Jolma]

I have my initial work here:

https://github.com/ajolma/gdal/commit/2335bc6222e8d8df7e4b5fcfe21a825c727ad549

what I've done so far:

* Recognize WCS:URL format

* Parse GetCapabilities XML (versions 1.0.0 to 2.0.1)

* Simple cache for various XML-files (PAM, WCS_GDAL, Capabilities, 
DescribeCoverage)

My goal is to support something like (1-3 work somehow, 3 only for 1.0.0 
- for 1.1.1 it issues a too large GetCoverage request, maybe I broke 
something(?))

1) gdalinfo WCS:URL-to-server

         this fetches, parses and caches GetCapabilities XML

2) pick a layer from the list (DescribeCoverage URL is given)

3) gdalinfo WCS:DescribeCoverage-URL

4) use the layer

I'll work on at least basic support for 2.0.1 - time permitting.

Notes:

* No tests yet in the autotest suite

* I'm testing against existing ArcGIS, GeoServer and MapServer servers 
on the net

* The namespace support in parsing XML may be a bit overkill, but anyway 
its there.

* There are a few small utility functions - some could perhaps be 
replaced by ones from port and some could perhaps be added there in some 
form; and all could be improved.

Ari


Even Rouault kirjoitti 23.10.2017 klo 13:19:
> Hi Ari,
>
>> It seems to me that the WCS driver could benefit from some love.
> That would be a good initiative!
>
> In the wished feature list, I could add:
>
> * improve test coverage, which is really low currently:
> https://rawgit.com/rouault/gdalautotest-coverage-results/master/coverage_html/frmts/wcs/wcsdataset.cpp.gcov.html
> One issue we have for testing is the lack of stable & reliable servers.
> One potential way of addressing this is to use a local HTTP server, like I did recently with the /vsis3/ (and similar)
> subsystems, where you can add stub endpoints. An extra advantage is that you can also easily test error situations.
> See
> - example of server start and end
> 	https://trac.osgeo.org/gdal/browser/trunk/autotest/gcore/vsis3.py#L126
>        https://trac.osgeo.org/gdal/browser/trunk/autotest/gcore/vsis3.py#L1906
> - example of installation of HTTP answers to expected requests:
>         https://trac.osgeo.org/gdal/browser/trunk/autotest/gcore/vsis3.py#L1258
>
> * WCS 2.0 support
>
>
> Even
>