Geopoint

A small class that helps manage latitude, longitude, and altitude points and calculates distance and compass heading between those points.

Usage

Creating a Geopoint is simple. Simply use the latitude and longitude:

$here = new Geopoint(33.99,-118.46); // latitude, longitude

You may also set the latitude and longitude manually:

$here = new Geopoint();
$here->latitude = 33.9;
$here->longitude = -118.46;

Calculating Distance to Another Point

The Geopoint class allows you to calculate the distance to another point. The default response returns meters.

$there = new Geopoint(33.81,-117.92);
$distance = $here->distanceToPoint($there); 
// returns 53707.148901519 (or 33.37 miles)

// to return miles instead of meters
$distance = $here->distanceToPoint($there, 'mi');
// returns 33.372075144605

To calculate distance, the Geopoint class uses the haversine formula, which takes into account the curvature of the planet.

Customizing the Radius

The Geopoint class uses the Earth's radius as the default, but allows you to customize the radius of the planet if necessary.

// say we're on Mars
$here->setSphericalRadius(3389500);

$distance = $here->distanceToPoint($there);
// returns 28573.241883931 (17.75 miles)

Calculating Compass Heading to Another Point

The Geopoint class allows you to calculate the compass heading to another point. The value returned is the heading in degrees, with 0˚ being North, 90˚ East, 180˚ South, and 270˚ West.

$heading = $here->compassHeadingToPoint($there); 
// returns 108.43494882292 (East Souteast)