[GRASS-user] Vector layer: percentage of shared perimeter

[Moritz Lennert]

On 22/04/09 18:47, Eduardo Corbelle wrote:
> Hello list:
> 
> I have an intuitive idea about an operation with vector polygons but I
> don't know how to accomplish (if even can be done). I will appreciate
> your comments and suggestions:
> 
> I have a vector layer consisting polygons of several classes. What I
> would like to calculate for each polygon (without regard of the class it
> belongs to) is the % of its perimeter that shares with adjacent polygons
> of a given class.

Using v.to.db several times with option set respectively to length and 
sides, followed by some SQL aggregation functions should do the trick 
(use a real SQL database backend, i.e. SQLite, PostgreSQL or MySQL).

Moritz