| project_vol() in IDL [message #11174] |
Thu, 26 February 1998 00:00  |
gpetty
Messages: 7
Registered: June 1997
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Junior Member |
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Today's my first day using IDL and I must say I am very impressed with
its capabilities (BTW, David Fanning's book made it vastly easier for
me to take the plunge and actually accomplish something useful during
this foray -- thanks, David!)
However, I have already run into what seems to be an annoying
limitation in project_vol() and am wondering whether I'm just
overlooking something.
What I want to do is take a 3-D volume, and project it onto a 2-D
plane. OK, fine, that's what project_vol() does. But for the life of
me, I can't figure out a way to make the values of the projected image
consist of the CUMULATIVE TOTAL of the data values along a ray.
Rather, it seems to insist on doing an average or something similar.
(Same complaint applies to voxel_proj(), by the way).
To give a simple example, if I define a cubical array to contain data
values equal to 0.1 everywhere, project_vol() makes the cube look the
same shade everywhere, whereas it ought (for my application) to look
translucent, with the edges of the cube "thinner" (i.e., darker) than
the center.
Playing with OPAQUE etc. has not led me to a satisfactory solution
yet. DEPTH_Q seems to do something different, based on geometric
depth rather than cumulative data value.
Any suggestions for a workaround?
thanks
Grant
P.S. As long as I'm posting to this NG, I might as well mention one
other suggested improvement to IDL that immediately comes to mind:
command line history/editing/completion capabilities, a la the UNIX
tcsh shell. It's a pain to have to retype an entire lengthy command
from scratch when all I want to do is change one parameter!
--
Grant W. Petty |Assoc. Prof., Atmospheric Science
Dept. of Earth & Atmospheric Sciences |Voice: (765)-494-2544
Purdue University, 1397 CIVL Bldg. |Fax: (765)-496-1210
West Lafayette, IN 47907-1397, USA |Email: gpetty@purdue.edu
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