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I have a road layer of a country. What method or plugin would you suggest, to find a single point furthest from any road

(but as you can see, there is a coastline, so points in the sea can't count)

The road layer looks like this:

road layer

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    Your question isn't well specified. A large area could be a convex polygon (perhaps much longer than "wide") paralleling a road, but no point in the polygon may be very far from a road. What are you trying to show? What have you already looked at? – BradHards Dec 16 '13 at 09:56
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    I am looking for two things: area by size that is surrounded by roads, and also a single point that is furthest from any roads. – normis Dec 16 '13 at 09:58
  • That sounds like two questions so I recommend that you edit this one to focus on whichever of the two things is important to have answered first. http://meta.stackexchange.com/questions/39223/one-post-with-multiple-questions-or-multiple-posts – PolyGeo Dec 16 '13 at 10:20
  • sorry about that.

    in that case: single point furthest from any road (but as you can see, there is a coastline, so points in the sea can't count)

     – normis Dec 16 '13 at 10:22
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    The question is for points, but the approach is the same: http://gis.stackexchange.com/questions/21575/calculating-distance-to-points-in-qgis – Matthias Kuhn Dec 16 '13 at 15:08
  • Check if you can generate a Voronoï diagram of your road network: The location you are looking for is a node of the Voronoï graph. – julien Dec 17 '13 at 21:56
  • @MatthiasKuhn could you post your comment as an answer so this thread no longer shows up on the unanswered list? Thanks! – underdark Apr 26 '14 at 22:35
  • @underdark Ok, done. I didn't want to plagiarize. Credits should go to Maxim Dubinin who answered the other question. Not sure how to deal with this. – Matthias Kuhn Apr 27 '14 at 09:13

1 Answers1

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First you need to rasterize the layer and then you can use proximity analysis from the GDAL Tools plugin: Raster > Analysis > Proximity.

More information can be found in the following related answer: Calculating distance to points in QGIS

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  • Thanks so much! Here is the result :) https://www.dropbox.com/s/m705f0kne4mpwci/Screenshot%202014-04-30%2011.46.43.jpg – normis Apr 30 '14 at 08:55