Re: [Matplotlib-users] Accessing WMS and ESRI REST services in Matplotlib

[Rich S. <rsi...@us...>]

Jeff,
Yep, that worked!  So here is a working example of OWSlib with
Basemap:  http://nbviewer.ipython.org/3900648/

I switched the Basemap projection to 'cyl' because we need to ensure
that Basemap and WMS are using the same projection, right?  (and since
I had requested EPSG:4326 from WMS, that's the 'cyl' in Basemap).

Thanks!
Rich

On Tue, Oct 16, 2012 at 11:38 AM, Jeff Whitaker <js...@fa...> wrote:
> On 10/16/12 8:48 AM, Rich Signell wrote:
>>
>> Klo & Jeff,
>>
>> I tried making a concrete example of using OWSlib with Basemap, but
>> althought the WMS image looks good, the warpimage does not.
>>
>> http://nbviewer.ipython.org/3899690/
>>
>> Do you see where I went wrong?
>>
>> Thanks,
>> Rich
>
>
> Rich:  warpimage assumes the image is of global extent.  In your example, I
> think you can just pass the image to the basemap imshow method with
>
> from matplotlib.image import imread
> import urllib2
> m.imshow(imread(urllib2.urlopen(url)),origin='upper')
>
> Klo previously mentioned there might be a problem with the png data from the
> WMS server being 'chunked', s you might have to use klo's imshow_chunked
> function
>
> http://www.mail-archive.com/mat...@li.../msg25618.html
>
>
> -Jeff
>
>>
>> On Sat, Oct 13, 2012 at 7:26 PM, klo uo <kl...@gm...> wrote:
>>>
>>> That's also what that snippet I linked does. You can add it to to Basemap
>>> and it should work.
>>>
>>> However Jeff suggested we use this tiny package OWSlib and handle WMS
>>> that
>>> way, which is better IMHO, but for some reason we did not got further
>>> reply.
>>>
>>>
>>>
>>> On Fri, Oct 12, 2012 at 1:31 PM, Rich Signell <rsi...@us...> wrote:
>>>>
>>>> WMS services are required to respond to  "GetCapabiltiies" request,
>>>> reporting what layers, styles, times, elevations, and projections they
>>>> have available.  So for example, using the Unidata WMS example below,
>>>> if we do:
>>>>
>>>>
>>>>
>>>> http://motherlode.ucar.edu:8080/thredds/wms/fmrc/NCEP/NAM/CONUS_12km/NCEP-NAM-CONUS_12km-noaaport_best.ncd?service=WMS&request=GetCapabilities
>>>>
>>>> we can see from the XML response that the Coordinate Reference Systems
>>>> supported are:
>>>>
>>>> <CRS>EPSG:4326</CRS>
>>>> <CRS>CRS:84</CRS>
>>>> <CRS>EPSG:41001</CRS>
>>>> <CRS>EPSG:3857</CRS>
>>>> <CRS>EPSG:27700</CRS>
>>>> <CRS>EPSG:3408</CRS>
>>>> <CRS>EPSG:3409</CRS>
>>>> <CRS>EPSG:32661</CRS>
>>>> <CRS>EPSG:32761</CRS>
>>>>
>>>> And for this server, the supported response types are:
>>>> <Format>image/jpeg</Format>
>>>> <Format>image/png</Format>
>>>> <Format>application/vnd.google-earth.kmz</Format>
>>>> <Format>image/gif</Format>
>>>>
>>>> So I guess one way to proceed if you wanted to use WMS in Matplotlib
>>>> and avoid reprojection in python would be to:
>>>> 1. do the WMS GetCapabilities request to find the available supported
>>>> Coordinate Reference Systems (which will vary with WMS server)
>>>> 2. setup Basemap to use one of these CRS
>>>> 3. use the bounding box of your current axis (in projection units) as
>>>> part of a GetMap request to the WMS.
>>>>
>>>> -Rich
>>>>
>>>> On Thu, Oct 11, 2012 at 12:16 AM, klo uo <kl...@gm...> wrote:
>>>>>
>>>>> I guess that's it?
>>>>>
>>>>> warpimage() as it is now, checks if passed image is url, so we can add
>>>>> additional check if image is url, with urlparse to deduce image
>>>>> coordinates
>>>>> and projection if present, then overlay it over already created Basemap
>>>>> object.
>>>>>
>>>>>
>>>>>
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>>>>
>>>>
>>>> --
>>>> Dr. Richard P. Signell   (508) 457-2229
>>>> USGS, 384 Woods Hole Rd.
>>>> Woods Hole, MA 02543-1598
>>>
>>>
>>
>>
>



-- 
Dr. Richard P. Signell   (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598