[yt-dev] Issue #725: off_axis_projection example gives blank image (yt_analysis/yt)

[Kacper Kowalik]

New issue 725: off_axis_projection example gives blank image
https://bitbucket.org/yt_analysis/yt/issue/725/off_axis_projection-example-gives-blank

Kacper Kowalik:

Following receipe:

```
#!python

from yt.mods import *
pf = load("HiresIsolatedGalaxy/DD0044/DD0044")
L = [1,1,0] # vector normal to cutting plane
north_vector = [-1,1,0]
W = [0.02, 0.02, 0.02]
c = [0.53, 0.53, 0.53]
N = 512
image = off_axis_projection(pf, c, L, W, N, "Density")
write_image(na.log10(image), "%s_offaxis_projection.png" % pf)
```

produce blank image and fails on `log10`. This snippet is a part of `source/visualizing/plots.rst`. I think the problem is caused by `W` but haven't investigated this in details. Also `na` should be changed to `np` ;-)

Responsible: ngoldbaum