Calculate the distance between longitudes and latitudes in PHP | Blog | George Harrison-Webb | Software Developer

# Calculate the distance between longitudes and latitudes in PHP

##### Author: George Harrison-Webb

Published:

Creating an as the crow flies distance tool within PHP is very simple and it stops you needing to have to use APIs

Prerequisits:
Basic PHP knowledge

Using this Haversine formulae is quick to implement in only a few lines of code' Looks complex? - Let's break it down
First, take your longitudes and latitudes to compare distances from.
You could use an API to convert an address to long and lats

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We need to set the radius of the earth - here I am using 6,378,137km
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Finally, using the following function, taking all the previously set variables, we will be using
the Haversine formulae to calculate the distance between the 2 given coordinates.
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function computeDistance(\$lat1, \$lng1, \$lat2, \$lng2, \$radius)
{
static \$x = M_PI / 180;
\$lat1 *= \$x; \$lng1 *= \$x;
\$lat2 *= \$x; \$lng2 *= \$x;
\$distance = 2 * asin(sqrt(pow(sin((\$lat1 - \$lat2) / 2), 2) + cos(\$lat1) * cos(\$lat2) * pow(sin((\$lng1 - \$lng2) / 2), 2)));

\$miles = round(\$meters * 0.00062137, 1);
return \$miles;
}

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After calling this function, it will give us the distance between 2 coordinates in miles, which you can of course adjust; depending on the measure you require

Category: How to guide

Tags:
PHP
Haversine formulae
Distance calculation
How to guide
As the crow flies