Give a table of linestrings (roads)
And a road with ogc_fid = X
In postgis how could I construct a linestring that is of length Y metres made up of roads starting from road X? I do not care which direction the line expands out of. It is important that the algorithm goes both ways to prevent dead ends.
My starter code was this:-
SELECT ST_LineMerge(ST_Collect(R.wkb_geometry)) FROM ROADS R WHERE ST_Touches(R.wkb_geomtry, (SELECT wkb_geometry FROM ROADS where ogc_fid = X))
But I am not on the right track as this returns a MultiLineString which means the LineMerge has not worked?