[postgis-users] match line with road segment
searchelite at gmail.com
Thu Jul 17 09:12:18 PDT 2008
Obe, Regina DND\MIS wrote:
> Now you do your make line. But you'll have to take into consideration
> what Paolo Rizzi said afterward. Not sure the easiest way to do that.
> So basically your process should look something like the below where
> trip_id is some fied that uniquely identifies each trip. The below snaps
> each point to closest road segment and then makes a line for each trip.
> It assumes the pt.gid is in the order of time travel. If you have a
> datetime field for each point, use that instead of the pt.gid.
> SELECT trip_id, ST_MakeLine(snapped_point) As trip_route
> ST_Line_Locate_Point(ln_geom, pt_geom)
> ) As snapped_point,
> SELECT DISTINCT ON (pt.gid)
> ln.the_geom AS ln_geom,
> pt.the_geom AS pt_geom,
> ln.id AS ln_id,
> pt.gid AS pt_id,pt.trip_id
> gps_points pt INNER JOIN
> road_table ln
> ST_DWithin(pt.the_geom, ln.the_geom, 10.0)
> ORDER BY
> pt.gid,ST_Distance(ln.the_geom, pt.the_geom)
> ) AS subquery ORDER BY trip_id, pt_id) As snapped_points
> GROUP BY travel_id;
> Hope that helps,
thanks a lot for the reply...i'll try the code you give me first thing
View this message in context: http://www.nabble.com/match-line-with-road-segment-tp18479996p18512194.html
Sent from the PostGIS - User mailing list archive at Nabble.com.
More information about the postgis-users