I can confirm, the images I got looks like the grids were not ordered correctly, patches of zones looks fine inbetween, but zone and zones do not match well at the boundary.

From

G.S.

On Fri, May 17, 2013 at 1:49 PM, Nathan Goldbaum <issues-reply@bitbucket.org> wrote:

New issue 570: Healpix volume rendering produces garbled, artifacted images
https://bitbucket.org/yt_analysis/yt/issue/570/healpix-volume-rendering-produces-garbled

Nathan Goldbaum:

Using the sample script from the docs:


```
#!python

from yt.mods import *
import yt.visualization.volume_rendering.camera as camera

pf = load("IsolatedGalaxy/galaxy0030/galaxy0030")
image = camera.allsky_projection(pf, [0.5,0.5,0.5], 100.0/pf['kpc'], 64, "Density")
camera.plot_allsky_healpix(image, 64, "allsky.png", "Column Density [g/cm^2]")
```

Produces the following image:


I also tried the manual method described further down in the docs:


```
#!python

rom yt.mods import *
import yt.visualization.volume_rendering.camera as camera

Nside = 32
pf = load("IsolatedGalaxy/galaxy0030/galaxy0030")
cam = camera.HEALpixCamera([0.5,0.5,0.5], 0.2, Nside, pf = pf, log_fields = [False])
bitmap = cam.snapshot()

import yt.utilities.lib as au
from numpy import pi
phi, theta = np.mgrid[0.0:2*pi:800j, 0:pi:800j]
pixi = au.arr_ang2pix_nest(Nside, theta.ravel(), phi.ravel())
img = np.log10(bitmap[:,0,0][pixi]).reshape((800,800))

import matplotlib.figure
import matplotlib.backends.backend_agg

fig = matplotlib.figure.Figure((10, 5))
ax = fig.add_subplot(1,1,1,projection='mollweide')
image = ax.imshow(img, extent=(-pi,pi,-pi/2,pi/2), clip_on=False, aspect=0.5)
cb = fig.colorbar(image, orientation='horizontal')

cb.set_label(r"$\mathrm{Column}\/\mathrm{Density}\/[\mathrm{g}/\mathrm{cm}^2]$")
canvas = matplotlib.backends.backend_agg.FigureCanvasAgg(fig)
canvas.print_figure("allsky.png")

```
Note that I had to update this a bit since amr_utils was renamed a while back.  This produces the following image:


While this looks more sensible, it's not clear to me that it is correct.


_______________________________________________
yt-dev mailing list
yt-dev@lists.spacepope.org
http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org

_______________________________________________
yt-dev mailing list
yt-dev@lists.spacepope.org
http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org