[postgis-users] Need an answer for somebody new to GIS and PostGIS

Brian Harbick brhar at mac.com
Sat Feb 3 11:26:16 PST 2007


I have a data set of 1 million rows of addresses that have lat/long.  
I do not know the source of the geocoding.

I need to be able to query the database for addresses within 10 miles  
of a point.

I have compared my attempts with results with results from Google API.

On one address, google said it was 8 miles away. PostGIS results said  
4 miles. Since, I live in the area that I tested 8 miles is most  
likely the correct answer.

I have tried using SRID -1 and 4326 and both do not match with google.

I admit I have been hacking at this for two weeks and read hundreds  
of posts in the forum, but have not found an answers that I can rely on.

I think that PostGIS is meant for point in polygon type queries,  
which I will need next. but, right now I am just trying to make sure  
I understand how to setup the geometry correctly to test for miles.

Please help point in the right direction with as much detail as  
possible.

Thank You.




More information about the postgis-users mailing list