> > These points were created from a GPX file along a road journey so they > crudely map to a line string
"Map matching" is the term often used to describe the process of assigning noisy Gpx points to underlying road network. > I was thinking compute the KNN distance for each point and remove those that > have a KNN < a threshold (say 100 metres) > Not sure what your data is like- Perhaps look at st_linesubstring where you can use generate series to produce a sequence of relative positions > Is that the best way to go about it?************** You may need to explore different methods - a method that works with your training dataset may not work so great on other Gpx datasets that were collected under different conditions _______________________________________________ postgis-users mailing list postgis-users@lists.osgeo.org http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users