[GRASS-user] Vector Topology: how to get a line from a boundary

[peter.loewe at gmx.de]

Hi,

here is a vector topology related issue:

After merging a base layer of adjacent polygons ("all the counties of an island") into one polygon ("the island's polygon") I am riddled by two issues:

1) How to get "just the outline" of the island ? Both v.type and v.extract with "type=boundary,line" produce an empty vector.

2) The main issue is to derive all counties of the island which lie on the shore (= ignore the counties which don't have a beach). How can a topological query be set up, saying "derive all the county polygons which share a common boundary with the islands shoreline" ?


Peter 

-- 
Dr. Peter Löwe
<peter.loewe at gmx.de>





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