QGIS and Python - create line with multiple points in postgis

Question

How can I create a line, with Python functions, with many points that are records in Postgis? Thank you

fgcartographix · Answer 1 · 2013-05-06 15:24:11Z

up vote 1 down vote

Not 100% what you are asking for, but why not creating the line in PostGIS first?

SELECT gps.gps_track, ST_MakeLine(gps.the_geom ORDER BY gps_time) As newgeom
FROM gps_points As gps
GROUP BY gps.gps_track;

That will create a different line for each gps track and order them by time. I use that to create bus routes, ordered by stop sequence.

Really fast too.

answered May 6 at 15:24

fgcartographix
427211

	Does not work, gives error in "order by" – user1573901 May 9 at 16:46
	Could you post your code? I'm not a PostGIS expert, I just happened to use that function 2-3 weeks ago, but it would help. – fgcartographix May 10 at 17:44
	I used it to create line from shapes points from gtfs: CREATE TABLE cit.ligne_tr AS SELECT p.shape_id, ST_MakeLine(geom) As geom FROM (SELECT * FROM cit.shapes ORDER BY shape_pt_sequence) p GROUP BY p.shape_id; – fgcartographix May 10 at 18:14

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