Re: [Matplotlib-users] How to properly define lat/lon WGS84 in basemap module?

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

Roger André wrote:
> Hi Jeff,
>
> I checked, and no the images are not geographically square.  I wonder 
> if I could approach this problem in a different way.  Would it be 
> possible for me to add tick marks and annotation to the image without 
> using the Basemap module alone?  My thinking is that I could bring the 
> image into Matplotlib, define a square figure, and then manually 
> define the size of the X and Y axes and label them.  Is it possible to 
> "decorate" an image this way, without using any projection support?
>
> Thanks for the help,
>
> Roger

Roger:  Sure, you could do that.  I'm not sure why you would want to 
display an image that's not geographically square as a square though.  
What's wrong with just letting Basemap show it as a rectange?

-Jeff
> --
>
> On Tue, Dec 16, 2008 at 4:43 AM, Jeff Whitaker <js...@fa... 
> <mailto:js...@fa...>> wrote:
>
>     Roger André wrote:
>
>         Hi All,
>
>         I have some square images which were generated via WMS
>         requests.  I have imported them into Matplotlib via
>         pil_to_array, and then display them in a Basemap instance
>         where I have defined the projection as:
>
>         m = Basemap(projection='cyl', lon_0=lon_0, llcrnrlon=ll_lon,
>         llcrnrlat=ll_lat, urcrnrlon=ur_lon,
>                    urcrnrlat=ur_lat, suppress_ticks=False)
>
>         While this works (it appears the tics are at the right
>         places), the image is no longer square, and I wonder if my
>         projection definition is correct.
>
>         Can someone show me what the correct Basemap parameters are
>         for working with images that are in EPSG:4326?
>
>         Thanks,
>
>         Roger
>
>
>     Roger:  The image will only be square if ur_lon-ll_lon =
>     ur_lat-ll_lat (i.e. the longitude range equals the latitude
>     range).  Is this the case?
>     -Jeff
>
>     -- 
>     Jeffrey S. Whitaker         Phone : (303)497-6313
>     NOAA/OAR/CDC  R/PSD1        FAX   : (303)497-6449
>     325 Broadway                Boulder, CO, USA 80305-3328
>
>


-- 
Jeffrey S. Whitaker         Phone  : (303)497-6313
Meteorologist               FAX    : (303)497-6449
NOAA/OAR/PSD  R/PSD1        Email  : Jef...@no...
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