function earth_distance_sql in Location 7.3

Same name and namespace in other branches

1. 5.3 earth.inc \earth_distance_sql()
2. 5 earth.inc \earth_distance_sql()
3. 6.3 earth.inc \earth_distance_sql()
4. 7.5 earth.inc \earth_distance_sql()
5. 7.4 earth.inc \earth_distance_sql()

Returns the SQL fragment needed to add a column called 'distance' to a query that includes the location table.

Parameters

float $longitude: The measurement point.

float $latitude: The measurement point.

string $tbl_alias: If necessary, the alias name of the location table to work from. Only required when working with named {location} tables.

Return value

string SQL fragment.

6 calls to earth_distance_sql()

location_handler_argument_location_proximity::query in handlers/location_handler_argument_location_proximity.inc

Set up the query for this argument.

location_handler_field_location_distance::click_sort in handlers/location_handler_field_location_distance.inc

Called to determine what to tell the clicksorter.

location_handler_field_location_distance::query in handlers/location_handler_field_location_distance.inc

Called to add the field to a query.

location_handler_sort_location_distance::query in handlers/location_handler_sort_location_distance.inc

Called to add the sort to a query.

location_search_search_execute in contrib/location_search/location_search.module

Implements hook_search_execute().

... See full list

File

./earth.inc, line 142

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_distance_sql($longitude, $latitude, $tbl_alias = '') {

  // Make a SQL expression that estimates the distance to the given location.
  $long = deg2rad($longitude);
  $lat = deg2rad($latitude);
  $radius = earth_radius($latitude);

  // If the table alias is specified, add on the separator.
  $tbl_alias = empty($tbl_alias) ? $tbl_alias : $tbl_alias . '.';
  $coslong = cos($long);
  $coslat = cos($lat);
  $sinlong = sin($long);
  $sinlat = sin($lat);
  return "(COALESCE(ACOS({$coslat}*COS(RADIANS({$tbl_alias}latitude))*({$coslong}*COS(RADIANS({$tbl_alias}longitude)) + {$sinlong}*SIN(RADIANS({$tbl_alias}longitude))) + {$sinlat}*SIN(RADIANS({$tbl_alias}latitude))), 0.00000)*{$radius})";
}