We can't have one in km, and one in meters. Use the SI unit "meter" everywhere.

Author: derickr

geospatial.c

@@ -535,7 +535,7 @@ PHP_FUNCTION(transform_datum)
 /* }}} */
 
 /* {{{ proto double haversine(GeoJSONPoint from, GeoJSONPoint to [, double radius ])
- * Calculates the greater circle distance between two points */
+ * Calculates the greater circle distance between two points in m */
 PHP_FUNCTION(haversine)
 {
 	double radius = GEO_EARTH_RADIUS;
@@ -554,7 +554,7 @@ PHP_FUNCTION(haversine)
 /* }}} */
 
 /* {{{ proto double vincenty(GeoJSONPoint from, GeoJSONPoint to [, long reference_ellipsoid ])
- * Calculates the distance between two points */
+ * Calculates the distance between two points in m */
 PHP_FUNCTION(vincenty)
 {
 	zval   *from_geojson, *to_geojson;

php_geospatial.h

@@ -114,9 +114,9 @@ const geo_helmert_constants osgb36_wgs84 = {
 #define GEO_DEG_TO_RAD 0.017453292519943295769236907684886
 /**
  * Calculate the radius using WGS-84's equatorial radius of
- * 6,378,1370m
+ * 6,378,137.0m
  */
-#define GEO_EARTH_RADIUS 6378.137
+#define GEO_EARTH_RADIUS 6378137.0
 #define GEO_SEC_IN_DEG 3600
 
 #define GEO_WGS84 0x0001

tests/Greenwich.phpt

@@ -22,8 +22,8 @@ $diferenceAiry = haversine(
 //lat long of merdian in Airy 1830 ideally long of 0
 var_dump($polar);
 //distance in m of difference from lat long and meridian
-echo round($diferenceWGS84 * 1000, 8),PHP_EOL;
-echo round($diferenceAiry * 1000, 8),PHP_EOL;
+echo round($diferenceWGS84, 8),PHP_EOL;
+echo round($diferenceAiry, 8),PHP_EOL;
 ?>
 --EXPECT--
 array(2) {

tests/geospatial_haversine_london_edinburgh.phpt

@@ -45,5 +45,5 @@ echo haversine($from, $to);
 */
 ?>
 --EXPECT--
-534.23703599421
+534237.03599421
 

tests/haversine.phpt

@@ -15,4 +15,4 @@ $to = array(
 var_dump(haversine($to, $from));
 ?>
 --EXPECTF--
-float(7.384698392931%d)
+float(7384.698392931%d)