On the PHP::Impact blog, Federico takes a look at finding geo-proximity to a find a location on a map and plot it and find the distance to another point - all with the help of PHP, Python and SQL.
Basically, what Iâ€™m doing is plotting a radius around a point on a map, which is defined by the distance between two points on the map given their latitudes and longitudes. To achieve this Iâ€™m using the Haversine formula (spherical trigonometry). This equation is important in navigation, it gives great-circle distances between two points on a sphere from their longitudes and latitudes.
Included in the post is the code for three different implementations - PHP, Python and SQL, all using that same formula.