[Numpy-discussion] announcing a ds9 module and a question about indices

Russell E Owen owen at astro.washington.edu
Fri Apr 16 13:41:01 EDT 2004

I wrote a simple module that allows one to display numarray arrays in 
ds9. It is available as part of the RO package (RO.DS9) 
<http://www.astro.washington.edu/owen/ROPython.html>, though it is 
presently self-contained. (I may well end up expanding it.) It sends 
a copy of the data, rather than trying to share a buffer.

It uses the command-line XPA interface instead of trying to use the 
underlying C XPA API. I'm curious if anybody has gotten a python 
interface to the C XPA API working. It looks a bit messy, but popen2 
messy in other ways (detecting errors without hanging on read, for 

I have what is probably a dumb question, but...if I load an array 
using PyFits and display it using ds9, I find that the array indices 
appear to be transposed relative to what I expect, i.e. numarray 
seems to use array[yind, xind].

Is this normal? Any hints on handling notation in code (I suspect 
there's not much I can do except document it)?

-- Russell

More information about the NumPy-Discussion mailing list