From octave-sources-request at bevo dot che dot wisc dot edu  Wed Apr 14 15:17:01 1999
Subject: Re: comp geom 
From: doolin at alpha-8 dot CE dot Berkeley dot EDU
To: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
Cc: doolin at alpha-8 dot CE dot Berkeley dot EDU, octave-sources@bevo.che.wisc.edu,         doolin@alpha-8.CE.Berkeley.EDU
Date: Wed, 14 Apr 1999 13:16:56 -0700


Excellent!

My previous code comes directly from some c code.

At some point I need centroids too, which I should be able 
to handle with this.   I will repost the modified code then.

>
>Here is another way to write this that avoids the loop, which may make
>it faster if the number of rows of p is large.

[]


>  polyarea ([1,1; -1,1; -1,-1; 1,-1])  ==>   4
>  polyarea ([1,1; 1,-1; -1,-1; -1,1])  ==>  -4

Yes, point order is important.  I will note that in the 
help part of the comments.

Thanks,

Dave D

>
>jwe



fwiw, if anyone has any code that will do a delauney
triangulation and export to a data file for gnuplot (ie blank line
separates triangles) it would save me some time...