Find nearest latitude and longitude points

Question

An question on latitude and longitude...Probably a silly one.

I have a set of latitude and longitudes for various locations.And, I have the latitude and longitude of the location in which I am in.

Now,I have to find the nearest places from my locations from the set of latitudes and longitudes I have. Is thee any special way of calculating it or it is just mere subtraction and checking the difference?

Could you please throw some light on this?

Thanks, J

Answer 1

It depends on how the points are placed.

For example - if most of the points are in a parking lot, then Euclidean Distance should work well.

In other cases - Geodesic Distance needs to be computed. This link should help you with more information.

Here is the conversion from Decimal format to Degree-Minute-Second format and vice versa.

cheers

Answer 2

You can use this SQL. it will select then nearest Lat, Lng from your DB entries.

SELECT id,lat,lng, ((ACOS(SIN(your_lat * PI() / 180) * SIN(lat * PI() / 180) + COS(your_lat * PI() / 180) * COS(lat * PI() / 180) * COS((your_long - lng) * PI() / 180)) * 180 / PI()) * 60 * 1.1515) AS distance FROM your_table_name HAVING distance <='10' ORDER BY distance ASC LIMIT 0,10

Hope this will help.