Thanks Peter, I managed to reach my goal using ST_LineInterpolatePoint. Starting from Start/End points, I add a new point along each linestring couple every meter until I get a significant offset (let's say 50 cm). Storing the resulting point allows to build lines from start to this new point for vizualization purposes. It's also necessary to consider that start/ending point come from digitization, which returns lines in a random way, important to adjust when using ST_LineInterpolatePoint.
Olivier -----Message d'origine----- De : postgis-users [mailto:[email protected]] De la part de Peter Devoy Envoyé : samedi 15 avril 2017 22:05 À : PostGIS Users Discussion Objet : Re: [postgis-users] Parallel linestring It is difficult to visualise the problem but perhaps some combination of ST_Difference and ST_Union could help you? If the lines do not exactly overlap you could perhaps first grow all geometries using ST_Buffer, then use ST_Union on the result, then maybe use ST_ApproximateMedialAxis to get a line? Good luck Peter _______________________________________________ postgis-users mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/postgis-users Hi I would appreciate to get some suggestions to detect and convert semi-parallel linestring. I have Y shaped linestrings composed of two linestrings with a common part. My goal is to detect that there are two lines composing the Y trunk, merging them into a new one (or keeping only one of them) and placing a new node at the Y center, to get a result composed of three linestrings, one trunk and two branches. Lines have the same starting point at the bottom of the Y. I tried to use toTopogeom but this does not help so far as it does not create a topopology when lines are parallels and close (0,03 meters as an example). Any idea to detect the parallel part would be appreciated. Thanks ! Olivier --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. https://www.avast.com/antivirus _______________________________________________ postgis-users mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/postgis-users
