Re: TRIANGULATE says "Points are co-linear, no solution"

[Jonathan Joseph <jj(at)scorpio.tn.cornell.edu>]

Sorry about the IDL code mixup, some cut/paste
problems - and the fact that I changed variable names from
from xx and yy to x and y (after pasting) but forgot to change
them all.  In other words, I noticed that in the code I supplied
that the readu command was missing the "y" at the end of it, and
the plot command was plotting xx and yy instead of x and y
(and probably shouldn't have had the /device on it).  And
I left off the "close, unit" command to
clean up the open file unit - though that shouldn't
have mattered.  Sorry, I was in a rush and can only
plead incompetancy.

Anyway,  I *AM* running idl 5.2 (well, 5,2,1), so presumably,
I should not have this problem.  I have created an IDL save file
now at the same place ftp://scorpio.tn.cornell.edu/jj/idl/
The file is called test.sav

The following code should work:
And by that, I mean (not work).
At least, it causes the error listed below on my
system (IDL 5.2.1 running on HP-UX 10.20)

;; restore the data
IDL> restore,'test.sav'
;; create a window
IDL> window
;; plot the data to see that it looks reasonable
IDL> plot,x,y,psym=3
;; try to triangulate the points
IDL> triangulate,x,y,tr,b
% TRIANGULATE: Points are co-linear, no solution.

I have tried the jitter business before to good effect.
I guess I'll go that route for now, I just didn't want to
accidentally jitter it too much and get "negative triangles"
when I applied the triangulation to the real positions.

As for what the data is...  Well, it has something to do
with stereo offsets between images.  The interesting coastline
effect is due to certain (dark) areas of the images are
not being processed - and there is also a polygonal clipping region
applied.  The actual images are of asteroid 253 Mathilde.

And I apologize for the ranting - I was a bit over the
edge yesterday afternoon.

-Jonathan