function earth_latitude_range in Location 5.3
Same name and namespace in other branches
- 5 earth.inc \earth_latitude_range()
- 6.3 earth.inc \earth_latitude_range()
- 7.5 earth.inc \earth_latitude_range()
- 7.3 earth.inc \earth_latitude_range()
- 7.4 earth.inc \earth_latitude_range()
2 calls to earth_latitude_range()
- location_views_filter_handler_proximity in contrib/
location_views/ location_views.module - _location_search in contrib/
location_search/ location_search.module - Implementation of hook_search(). (forwarded from location.module)
File
- ./
earth.inc, line 146 - Trigonometry for calculating geographical distances. All function arguments and return values measure distances in metres and angles in degrees. The ellipsoid model is from the WGS-84 datum. Ka-Ping Yee, 2003-08-11
Code
function earth_latitude_range($longitude, $latitude, $distance) {
// Estimate the min and max latitudes within $distance of a given location.
$long = deg2rad($longitude);
$lat = deg2rad($latitude);
$radius = earth_radius($latitude);
$angle = $distance / $radius;
$minlat = $lat - $angle;
$maxlat = $lat + $angle;
$rightangle = pi() / 2;
if ($minlat < -$rightangle) {
// wrapped around the south pole
$overshoot = -$minlat - $rightangle;
$minlat = -$rightangle + $overshoot;
if ($minlat > $maxlat) {
$maxlat = $minlat;
}
$minlat = -$rightangle;
}
if ($maxlat > $rightangle) {
// wrapped around the north pole
$overshoot = $maxlat - $rightangle;
$maxlat = $rightangle - $overshoot;
if ($maxlat < $minlat) {
$minlat = $maxlat;
}
$maxlat = $rightangle;
}
return array(
rad2deg($minlat),
rad2deg($maxlat),
);
}