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

[R. A. <ra...@gm...>]

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
--

On Tue, Dec 16, 2008 at 4:43 AM, Jeff Whitaker <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
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