[GRASS-dev] matplotlib example script

[Michael Barton]

Yann,

Have you tried this on a dataset without NAN values?

Michael
______________________________
C. Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University
Tempe, AZ  85287-2402
USA

voice: 480-965-6262; fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

On Jul 25, 2008, at 4:09 PM, Yann Chemin wrote:

> Hi,
>
> after chmod +x, it created a nice histogram of elevation.10m.
> So I tried on floating point image created by some process.
>
> here is the problem:
> Traceback (most recent call last):
>  File "/home/yann/histogram_mpldemo.py", line 173, in <module>
>    main()
>  File "/home/yann/histogram_mpldemo.py", line 159, in main
>    alpha=0.75)
>  File "/usr/lib/python2.5/site-packages/matplotlib/axes.py", line  
> 6035, in hist
>    normed=bool(normed), new=True)
>  File "/usr/lib/python2.5/site-packages/numpy/lib/function_base.py",
> line 236, in histogram
>    range = (a.min(), a.max())
> ValueError: zero-size array to ufunc.reduce without identity
>
>
> this happens because the data has NAN (see r.info output):
> Range of data:    min = nan  max = nan
>
> Is there a way to discard NAN in a.min() and a.max() calculations?
> Or is there a NAN-resistant mode in matplotlib?
>
> Yann