Re: [Matplotlib-users] basemap and contouring

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

  On 9/13/10 8:02 AM, mdekauwe wrote:
> Hi,
>
> Well I tried...
>
> numrows = 17
> numcols = 16
> ulat, llat, ulon, llon = 15.61, 15.15, -1.32, -1.74
> m = Basemap(projection='geos', lon_0=0.0, llcrnrlon=llon,
>                  llcrnrlat=llat, urcrnrlon=ulon, urcrnrlat=ulat,
>                  resolution='c')
>
> data2 = np.random.sample((17,16))
> print 'DATA2 shape:', data2.shape
> x = np.linspace(-1.74, -1.32, 16)
> y = np.linspace(15.15, 15.61, 17)
> print 'x shape:', x.shape
> print 'y shape:', y.shape
> px, py = m(x, y)
>
>
> which gives...
>
> DATA2 shape: (17, 16)
> x shape: (16,)
> y shape: (17,)
>
> So that looks OK. Turns out the error now comes at the line px, py = m(x,
> y). So perhaps I am doing the basemap step incorrectly?
>
> Traceback (most recent call last):
>    File "./recontour_plot.py", line 83, in<module>
>      px, py = m(x, y)
>    File "/users/eow/mgdk/sun4u//lib/python/mpl_toolkits/basemap/__init__.py",
> line 823, in __call__
>      return self.projtran(x,y,inverse=inverse)
>    File "/users/eow/mgdk/sun4u//lib/python/mpl_toolkits/basemap/proj.py",
> line 241, in __call__
>      outx,outy = self._proj4(x, y, inverse=inverse)
>    File "/users/eow/mgdk/sun4u//lib/python/mpl_toolkits/basemap/pyproj.py",
> line 193, in __call__
>      _Proj._fwd(self, inx, iny, radians=radians, errcheck=errcheck)
>    File "_proj.pyx", line 56, in _proj.Proj._fwd (src/_proj.c:725)
> RuntimeError: Buffer lengths not the same
>
>
Martin:

You need a meshgrid

x,y  = np.meshgrid(x,y)

just *before* (not after)

px,py = m(x,y)

so that x and y have the same shape as data2.

-Jeff

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