r.line stops partway through

[Simon Cox]

I apologise for my repeated failure to get this message through
successfully - I think I've just figgured out how I was confusing the
mailer, so I'll try again.


Who has used r.line to do raster -> vector conversion?
I am trying to use it on a scanned contour separation.
I am finding that it is working fine, but seems to stop
part way down my data - ie I get ok results down to a
certain row, and then nothing lower.  During running I get
a load of lines saying things like

> .
> .
> .
> update_list:  isolated cell (284,357)
> update_list:  isolated cell (288,71)
> update_list:  isolated cell (289,356)
> crowded cell 5H (301,723) -continuing
> crowded cell 5H (321,852) -continuing
> update_list:  isolated cell (353,732)
> update_list:  isolated cell (353,800)
> update_list:  isolated cell (360,903)
> update_list:  isolated cell (363,687)

and then it stops - apparently the last row processed is around 363.

Is there some limit to the number of entries that it will
take in the "update_list" which is not described
in the man page?  Why am I only getting partial success?
How can I remove the "isolated cells" prior to running
r.line?  (Do I have to resort to r.mapcalc for morphological
operations other than those offered by r.thin and r.grow?)

(The map is very busy, and some of the contours are so
close together that they merge in the scanned image.  As
it is a karst area, there are lots of wierd features and
sink holes also shown on the contour layer.  I was hoping to
be able to do the cleaning up in v.digit as I find d.rast.edit
a bit clunky.)

Thanks

Simon Cox
----
___________________________________________________
      __  L     Dr Simon Cox			
   ,~'  L_|\    VIEPS Department of Earth Sciences, 
,-'         \   Monash University, Clayton Vic 3168        
(            \  Australia
\    ___     /          Phone +61 3 565 5762
 L,~'   "\_x/           Fax   +61 3 565 5062
           u    simon at cerberus.earth.monash.edu.au
___________________________________________________