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I am doing a piece of analysis work looking at distances along a network in GRASS. Most of the analysis involves finding which parts of the network are within 600m of a series of points. GRASS does this very well using the v.net functions.

I've got stuck on trying to identify which parts of a network are within 600m of more than two points in the series.

Does anyone have any ideas how I could do this within GRASS?

I'm using the GRASS plugin in QGIS.

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  1. Take line layer , go Vector-> geoprosessing tools -> buffer (600m) -> save results layer
  2. Go Vector-> geoprosessing tools -> Intersects buffer layer and points layer -> save results take results , and count points per series in one buffer. (3. not 100% about this)

OR replace 2. with

  1. Go Vector-> count points in polygon (this probably wont give you answer ) Open attribute table and select by expression and make query from count + series id + point count

OR

  1. Go Vector-> count points in polygon (this probably wont give you answer ) Open attribute table and select by expression and make query from count + series id + point count

    OR

  2. Use Vector Spatial Query tool ( this might be plugin , not 100 %)

  • That would be an ideal way to do this with a standard buffer - problem is that it's a network analysis - in effect the distance along a line network from a series of points. It is walking distance along paths and pavements from amenities, rather than "as the crow flies" analysis that you get from using the geoprocessing tools. That's why I've been using the v.net GRASS commands. – Neil Benny Feb 3 '14 at 14:24
  • ah.. understood question wrong. – simplexio Feb 3 '14 at 15:00

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