[GIS] How to find nearest line from point using PostGIS

linestringpostgispostgis-2.0postgresql

I have a table of Roads in PostGIS which geometry is "geometry(MultiLineString,4326)".

Its attribute are

gid osm_id name ref type oneway bridge maxspeed geom

Now i want to know the closest Road from latitude and longitude.

Also I want to set some distance from that Line/Road like 20m both side and if the point is within that distance then it should give the name of that line else not.

Best Answer

SELECT name,ref,type,ST_Distance(ST_Buffer(r.geom,20),ST_SetSRID(ST_MakePoint(lon, lat),4326)) 
FROM roads r 
ORDER BY 4 ASC 
LIMIT 1;

For point in lon/lat coordinates:

SELECT name,ST_Distance(r.geom,ST_SetSRID(ST_MakePoint(lon, lat),4326)) FROM roads r ORDER BY 2 ASC LIMIT 1;
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