[GRASS-user] How to get adjacent areas

[Moritz Lennert]

On 11/06/07 19:34, Maciej Sieczka wrote:
> Hazael Maldonado Torres wrote:
>> Hi there,
>>
>> I am new in the GRASS world and the reason I am using it is because I
>> need to obtain the adjacent areas for a given area in the map. So far,
>> I have found a way to obtain this information. I found that
>> v.neighbors with the option "count" tells you how many neighbours,
>> however, I need to know which ones so I can do some other analyses.
>>
>> I hope someone out there can help me.
> 
> v.to.db option=sides

If I understand correctly this only works for boundaries, not for 
areas/centroids.

So (again IIUC), to get a list of neighbors of an area you would have to:

- attribute a category value to each boundary
- use v.to.db option=sides to get the areas adjacent to each boundary
- for each area:
	- search the boundaries to which this area is adjacent
	- search the other areas adjacent to these boundaries

Might be worth looking into how difficult it would be to apply the 
'sides' option to centroids and find adjacent centroids...

Moritz