Ya, it's near the southern tip of India, a point in Sri Lanka. x, y has been given correct. I used 4326 as the SRID.
Stephen Woodbridge wrote: > > You need to read up on pgRouting and probably join the pgRouting list > > http://pgrouting.postlbs.org/ > http://lists.postlbs.org/mailman/listinfo/pgrouting-users > > -Steve > > Nalin C wrote: >> 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 >>>> >>>> >>> >> > > _______________________________________________ > 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-tp26559254p26562727.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
