[GRASS-dev] Re: [GRASS-user] v.clean tool=prune - 'thresh' interpreted wrong?

[Markus Neteler]

On Tue, Oct 03, 2006 at 02:23:56PM +0200, Moritz Lennert wrote:
...
> Doesn't
> 
> 20 5
> 30 7.5
> 40 10
> 
> Define a straight line ? I would guess that the prune tool prunes all 
> "unneccessary" nodes on a straight line, i.e. any node which is not 
> necessary to define the line, and this whatever the threshold.
> 
> The threshold only applies in cases of change of direction (i.e. angles).
> 
> Just another example of the need for much more documentation for 
> v.clean, including example diagrams like the one for the rmsa tool.

Fully agreed... but let me reiterate that a different pruning
algorithm might be the best solution (e.g. Douglas-Peucker which
is found as C code on the GMT site). The current one doesn't even work
in LatLong.

Markus