How to do Reverse Geocoding from MySQL/PostGIS Sql ???

Question

I want to do reverse geocoding from MySQL or PostGIS SQL.

I have shapefile up to town level of India. So I have a geometry boundary for each town.

What I want is to first find the nearest point from the current position and check that point is in which towns.

I want to get the result in this format: Towns, District, State, Country

I dont have knowledge of PostGIS SQL but I know MySQL. But if anyone can help me I will use the PostGIS SQL also.

So I want fastest way to do reverse geocoding.

Thank you.

I'm having trouble understanding what you are wanting by saying : "What I want is to first find the nearest point from the current position and check that point is in which towns." Do you have a set of points which you wish to classify as belonging to a town, district, state and country?

GIS-Jonathan · Answer 1 · 2012-11-01 10:55:02Z

So i assume that you have 4 levels of polygons , Country polygons have State polygon inside and State polygons have District polygon inside...

Also i assume that you have all those polygon in one table

SELECT * FROM india_polygons as i , point p WHERE ST_Contains(i.the_geom , p.the_geom) IS TRUE AND p.id = 42

Is one way of doing it

Offcourse fastest way is pre calculate Town, District, State, Country relation and then do only spatial search wher you find which town point is in.

works in postgis , maybe in mysql

All this polygon is in different table. State,District,Town I want to retrieve the each name from that polygon which is in boundary.

1 Answer