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

[Maciej Sieczka]

Moritz Lennert wrote:

> To echo Hamish' question: Do you need to remove vertices from lines
> without changing the form of the line, or do you want to generalize the
> form of the line (in the way that is shown here:
> http://mpa.itc.it/markus/como2006/img9.html ?

The latter. I want to remove all the vertices that are distant from the
line starting node not more than the give thresh. A line:

x--o1-o2-->----o3--x

"x" - node
"o" - vertex
">" - line direction
"-" - 1 length unit

thresh=3 would remove o1, thresh=5 the o1 and o2 and so on

>> 2. This is a bug or a lacking documention, so either should be fixed,
>> no matter what other pruning algorithm is added to Grass.
> 
> It actually also seems to be an ambiguity as to what pruning actually
> means:
>
> - remove unnecessary nodes, or
> - generalize

Using that terminology - according to current Grass documentation
(v.clean manual and the source code comments) v.clean tool=prune means
"generalize".

Maciek