Front & Back Development

# Calculating the distance between two points using latitude and longitude

How to handle distance bettween latitude/longitude points.

Haversine Formula
http://en.wikipedia.org/wiki/Haversine_formula

Php Function to calculate distance between 2 points:

```function distance(\$lat1, \$lon1, \$lat2, \$lon2) {

\$pi80 = M_PI / 180;
\$lat1 *= \$pi80;
\$lon1 *= \$pi80;
\$lat2 *= \$pi80;
\$lon2 *= \$pi80;

\$r = 6372.797; // mean radius of Earth in km
\$dlat = \$lat2 - \$lat1;
\$dlon = \$lon2 - \$lon1;
\$a = sin(\$dlat / 2) * sin(\$dlat / 2) + cos(\$lat1) * cos(\$lat2) * sin(\$dlon / 2) * sin(\$dlon / 2);
\$c = 2 * atan2(sqrt(\$a), sqrt(1 - \$a));
\$km = \$r * \$c;

//echo '
'.\$km;
return \$km;

}```

Mysql Query getting the nearest points (objects,products,users, what ever ….)
This SlideShare could help you optimize your querys, since make querys and manipulating coords are time consuming with big db’s.

Doing some testing before coding anything
http://www.movable-type.co.uk/scripts/latlong.html Beto López
"Full stack" web developer focused in maintenance and bug fixing.Wordpress, Prestashop, HTML, CSS, Javascript, Php and Mysql. Also open source collaborator. Linkedin y Twitter.