+----------------------------------------- Jeff Whitaker -----------+
>
> Here's the basic idea:
>
> 1) read the germany.dat file, use it to create a _geoslib Poly instance,
> i.e.
>
> from mpl_toolkits.basemap import _geoslib
> b = np.asarray([lons,lats]).T # lons and lats are lists.
> germanypoly = _geoslib.Polygon(b)
>
> 2) loop over all the points on the grid and do
>
> inside = _geoslib.Point((lonpt,latpt)).within(germanypoly)
>
> filling a boolean array with the values.
>
> 3) use this boolean array as a mask to create a masked array from your
> data. Then, when you plot the masked array with contourf only the
> points inside germany will be contoured.
>
> Give this a try and let us know how it goes.
>
> -Jeff
>
because of islands it doesn't work as expected i guess?
here is what i did:
>>> bmap = Basemap(projection='aeqd', ...)
>>> x, y = bmap(lons, lats)
>>> npoints = 300
>>> xi = np.linspace(np.amin(x), np.amax(x), npoints*.7178)
>>> yi = np.linspace(np.amin(y), np.amax(y), npoints)
>>> zi = griddata(x, y, var, xi, yi)
>>> inside = np.zeros_like(zi)
>>> lon, lat = np.loadtxt('germany-lon-lat-np.arr')
>>> bx, by = bmap(lon, lat)
>>> b = np.asarray([bx, by]).T
>>> poly = _geoslib.Polygon(b)
>>> i = 0
>>> # i know this is slow, but ...
>>> for y in yi:
>>> for x in xi:
>>> inside.flat[i] = _geoslib.Point((x,y)).within(poly)
>>> i += 1
>>> mzi = ma.masked_array(zi, mask=inside)
here is what it looks like:
http://rokuko.net/test.png
matlab includes NaNs right before and after islands in the lon
lat lists, is there something similar ?
thank you so far, best regards
PS
http://rokuko.net/germany-lon-lat-np.arr
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