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-tp26559254p26559836.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
