Also, can you please suggest me the functions that can be used for points 2 and 3 ? I'm totally a newbie to postgis.
In point 2, it would be great if the path can start from in front of the hospital, instead a vertex in roads table. Nalin C wrote: > > Hi Steve, > > Thank you for the quick reply. > > I observed that the results returned by : > > select name, the_geom from hospitals order by > distance_sphere(setsrid(makepoint(79.877778, 6.914722), 4326), the_geom) > asc limit 3; > > are not the closest hospitals to the given accident point. I'm not sure > what has gone wrong. > > > Thanks, > > Nalin > > > > Stephen Woodbridge wrote: >> >> Nalin C wrote: >>> Hi, >>> >>> I have two tables for roads and hospitals. I'm looking for suitable >>> pgrouting function(s) for following scenario. >>> >>> Given the accident point (in point geometry), finding the least distant >>> hospital and draw the path. >>> >>> Following functionality is needed. >>> >>> 1. One end of the drawn path needs to start from in front of the closest >>> hospital (which is in hospitals table). >>> 2. Path needs to stop from the accident point on road. >>> >>> I'm new to pgrouting and appreciate your help. >> >> You have a few discrete tasks. Assuming you have the location of the >> accident: >> >> 1) Select say the three closest hospitals based on straight line >> distance. (x,y) is the location of the accident. >> >> select name, the_geom from hospitals where order by >> distance_sphere(setsrid(makepoint(x,y), 4326), the_geom) asc limit 3; >> >> 2) then use pgRouting to use the Hospital location as start and the >> accident as end and comput the routes >> >> 3) compare the routed distances and select the shortest. >> >> -Steve W >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > > -- View this message in context: http://old.nabble.com/Path-to-closest-neighbor-tp26559254p26560083.html Sent from the PostGIS - User mailing list archive at Nabble.com. _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
