Re: [Matplotlib-users] Background basemaps in Basemap

[Jeff W. <js...@fa...>]

On 8/25/12 7:53 AM, Benjamin Root wrote:
>
>
> On Saturday, August 25, 2012, Jeff Whitaker wrote:
>
>     On 8/24/12 10:20 PM, klo uo wrote:
>     > On Sat, Aug 25, 2012 at 1:26 AM, Jeff Whitaker wrote:
>     >> Oh sure, it's simple!
>     >>
>     >> http://www.google.com/patents?id=J4YOAAAAEBAJ&dq=6618053
>     > Hi Jeff,
>     >
>     > thanks for your reply.
>     >
>     > I was hoping to get response if there are ideas how this unfortunate
>     > performance can be avoided. If there are some thoughts or if it's
>     > closed case.
>
>     Klo:  It's not a closed case - but I have no idea how to do it.  If
>     you'd like to try to implement something, your contribution would be
>     welcome.
>     >
>     > About GIS web-services, I thought maybe extending Basemap and
>     > providing interface to some of available online mapping services.
>     > For example arcgis is just one of them, and allows using their
>     online
>     > map service to arbitrary application, while exposing REST
>     >
>     (http://resources.arcgis.com/en/help/rest/apiref/index.html?mapserver.html)
>     > and SOAP service with full WSDL description
>     >
>     (http://services.arcgisonline.com/ArcGIS/services/World_Imagery/MapServer?wsdl)
>     > and documentation. REST requests cover all of their services while
>     > SOAP is limited and a bit harder to code in this example. Services
>     > offer much more than it's needed to be paired in Basemap, as can be
>     > seen from documentation, with any imaginable projection and what
>     not.
>     >
>     > As an example of using the service here is image:
>     http://i.imgur.com/RpUFv.png
>     > and here is it's simple source code that executes unnoticeable
>     in second:
>     > ========================================
>     >    import matplotlib.pyplot as plt
>     >    import urllib2
>     >
>     >    lon1 = -10; lon2 = 30; lat1 = 30; lat2 = 60
>     >    basemap_url =
>     >
>     "http://server.arcgisonline.com/ArcGIS/rest/services/World_Physical_Map/MapServer/export?bbox=%d,%d,%d,%d&bboxSR=4326&size=1024,768&dpi=128&format=png32&f=image"
>     > % (lon1, lat1, lon2, lat2)
>     >    overlay_url =
>     >
>     "https://ogcie.iblsoft.com/sigwx?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&LAYERS=ASXX&WIDTH=1024&HEIGHT=768&CRS=EPSG:4326&BBOX=%d,%d,%d,%d&TRANSPARENT=TRUE&STYLES=&FORMAT=image/png"
>     > % (lon1, lat1, lon2, lat2)
>     >
>     >    plt.figure(figsize=(8, 6), dpi=128, facecolor='w')
>     >    plt.imshow(plt.imread(urllib2.urlopen(basemap_url)))
>     >    plt.imshow(plt.imread(urllib2.urlopen(overlay_url)))
>     >    plt.gca().axison = False
>     >    plt.savefig("scene.png", dpi=128, transparent=True)
>     > ========================================
>     >
>     > As both "basemap map" and overlay image use same CRS, this seems
>     > doable with just MPL.
>     >
>     > Having such service paired in Basemap as a feature looks very
>     > promising to me. I don't know much about MPL and Basemap design,
>     as if
>     > all above talk is easy and then acceptable for implementation, but
>     > that's roughly what I had in mind for web-services - as additional
>     > feature for replacing bloated background maps provided, which
>     does not
>     > have such quality to justify low performance.
>     It looks like you are fetching an image over a specified region and
>     displaying it with matplotlib.  That's very useful, but it doesn't
>     solve
>     the zooming problem you mentioned.  Still, it's a good start and would
>     be nice to have in basemap.
>
>     Sorry for sounding so dismissive in my earlier reply.  How do you
>     think
>     web map services could be integrated into Basemap?  Do you see this
>     mainly as a faster and more general alternative to the 'bluemarble' or
>     'warpimage' methods, where you can specify a web map service and have
>     the appropriate tile that fits the map projection region fetched and
>     displayed automatically?
>
>     -Jeff
>
>
> If I could chime in for a quick moment, perhaps one could consider a 
> specialized backend extension that would provide the web services 
> communication?  This way, when panning and zooming, the backend would 
> know the limits and fetch (and optionally cache) the requested tiles 
> from the connected service.
>
> Mind you, I don't think this quite falls into the scope of the mpl or 
> Basemap project, but such a backend would be a powerful project on its 
> own.
>
> Cheers!
> Ben Root
>
Maybe such a thing could be built using owslib?

http://geopython.github.com/OWSLib/

-Jeff