[OSGeo-Discuss] geospatial algorithm to create area midway boundaries from lines ?

Darafei "Komяpa" Praliaskouski me at komzpa.net
Mon Mar 9 01:19:31 PDT 2020


Hi,

I had reasonably good results for something similar combining these
things in PostGIS:
 - ST_Segmentize(geom, ST_Length(geom)/ST_NPoints(geom)) to generate
extra points on long straight runs of your lines;
 - ST_DumpPoints to extract just the points;
 - ST_VoronoiPolygons to generate Voronoi coverage of these;
 - ST_Union and GROUP BY initial object's ID to get back areas.

You can control precision of approximation tweaking maximum segment
length in ST_Segmentize.

On Sat, Mar 7, 2020 at 1:36 AM karsten <karsten at terragis.net> wrote:
>
> Hi All,
>
> a general geospatial question to all:
> I am trying to find out if there is any existing geospatial algorithm (in any open Open Source Geospatial software) that would allow to use a network of lines as a start point and expand those in such a way that I can create new area boundaries for each of the lines "coverage area". What I mean with that is if one could "buffer" the lines out in such a way to create boundaries where any potential buffers would meet at the middle way point between the lines so that in the end I could have an area within that is the starting line. On example could look like this (5 hand drawn lines in red and corresponding colored areas that I would want to create). Note that is exact but to communicate the idea) see http://terra5.terragis.net/sites/html/aeras_for_lines%20copy.png
>
> It's kind of similar to Thiessen polygons but for lines instead of points...
>
> One preference would be if there was something that could be used programmatically on large data sets ...
>
> Cheers
> Karsten
>
> Karsten Vennemann
> www.terragis.net
>
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Darafei Praliaskouski
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