Hi! First case sounds like ST_Snap.
For second case, if you are not going to write an extending loop I would try to get the polygon after buffering and then try with ST_StraightSkeleton and ST_ApproximateMedialAxis. Can you share a dataset to play with? пн, 27 авг. 2018 г. в 19:34, Hemant Bist <[email protected]>: > Hi, > Is there something already written that can help me do the following? > > I need to "extend" the line segments by a small amount to see if they can > be joined. The use cases are > 1) Joining line segments that should be joined in reality but in the data > (linstrings) they have a small gap. > 2) The vector lines (multiple linestrings) are dashed line representation > of real line .e.g. representing a road by dashed line of 4mm dashes with > gap of 1 mm between them. > I am willing to live with error cases where some line segments are joined > when they should not be. The output I need should be > > I cannot do st_buffer(st_union(st_buffer( line_geometry, epsilon)), > -epsilon) as it turns the lines into area. But visually these areas look > close to what I need. > The other drawback of st_buffer is that it extends line in all directions, > instead of extending line segments in expected directions. > > Currently the only possible "solution" I have in mind is to write > something custom to extend the individual line strings and then do st_union. > > If there are something available in other tools like gdal, grass, I will > be happy to look at them. Currently I don't know of any solutions in other > tools as well. > Thanks, > HB > > > > > _______________________________________________ > postgis-users mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/postgis-users -- Darafei Praliaskouski Support me: http://patreon.com/komzpa
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