Ian,
> I'm running into a crash while trying to construct a
> tri.LinearTriInterpolator. Here is the short version of the code:
>
> import netCDF4
> import matplotlib.tri as tri
>
> var = netCDF4.Dataset('filename.cdf').variables
> x = var['x'][:]
> y = var['y'][:]
> data = var['zeta_max'][:]
> elems = var['element'][:, :]-1
>
> triang = tri.Triangulation(x, y, triangles=elems)
>
> # this crashes the python interpreter
> interp = tri.LinearTriInterpolator(triang, data)
>
> The data arrays (x, y, data, elems) are fairly large (>1 mio elements),
> all
> represented as numpy arrays (as returned by netCDF4). The 'data' array is
> a
> masked array and contains masked values.
>
> If somebody cares, I'd be able to post a link to the netCDF data file
> causing this.
>
> All this happens when using matplotlib 1.3.1, Win32, Python 2.7.
>
> Any help would be highly appreciated!
> Regards Hartmut
>
> Hartmut,
> That is an excellent issue report; all the relevant information and
> nothing extraneous. Hence the quick response.
> The second argument to TriLinearInterpolator (and other TriInterpolator
> classes), i.e. your 'data' array, is expected to be an array of the same
> size as the 'x' and 'y' arrays. It is not expecting a masked array. If a
> masked array is used the mask will be ignored, and so the values behind
> the mask will be used as though they were real values. If my memory of
> netCDF is correct, this will be whatever 'FillValue' is defined for the
> file, but it may depend on what is used to generate the netCDF file.
> I would normally expect the code to work but produce useless output. A
> crash is possible though. It would be best if you could post a link to
> the netCDF file and I will take a closer look to check there is not
> something else going wrong.
Thanks for the quick response!
Here is the data file: http://tinyurl.com/ms7vzxw. I did some more experiments.
The picture stays unchanged, even if I fill the masked values in the array with
some real numbers (I'm not saying that this would give me any sensible
results...):
import netCDF4
import matplotlib.tri as tri
var = netCDF4.Dataset('maxele.63.nc').variables
x = var['x'][:]
y = var['y'][:]
data = var['zeta_max'][:]
elems = var['element'][:, :]-1
triang = tri.Triangulation(x, y, triangles=elems)
data = data.filled(0.0)
# this still crashes the python interpreter
interp = tri.LinearTriInterpolator(triang, data)
Thanks again!
Regards Hartmut
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