Diese raffinierte kleine mySQL-Funktion, die ich geschrieben habe, sollte definitiv den Zweck für Sie erfüllen.
BEGIN
DECLARE x decimal(18,15);
DECLARE EarthRadius decimal(7,3);
DECLARE distInSelectedUnit decimal(18, 10);
IF originLatitude = relativeLatitude AND originLongitude = relativeLongitude THEN
RETURN 0; -- same lat/lon points, 0 distance
END IF;
-- default unit of measurement will be miles
IF measure != 'Miles' AND measure != 'Kilometers' THEN
SET measure = 'Miles';
END IF;
-- lat and lon values must be within -180 and 180.
IF originLatitude < -180 OR relativeLatitude < -180 OR originLongitude < -180 OR relativeLongitude < -180 THEN
RETURN 0;
END IF;
IF originLatitude > 180 OR relativeLatitude > 180 OR originLongitude > 180 OR relativeLongitude > 180 THEN
RETURN 0;
END IF;
SET x = 0.0;
-- convert from degrees to radians
SET originLatitude = originLatitude * PI() / 180.0,
originLongitude = originLongitude * PI() / 180.0,
relativeLatitude = relativeLatitude * PI() / 180.0,
relativeLongitude = relativeLongitude * PI() / 180.0;
-- distance formula, accurate to within 30 feet
SET x = Sin(originLatitude) * Sin(relativeLatitude) + Cos(originLatitude) * Cos(relativeLatitude) * Cos(relativeLongitude - originLongitude);
IF 1 = x THEN
SET distInSelectedUnit = 0; -- same lat/long points
-- not enough precision in MySQL to detect this earlier in the function
END IF;
SET EarthRadius = 3963.189;
SET distInSelectedUnit = EarthRadius * (-1 * Atan(x / Sqrt(1 - x * x)) + PI() / 2);
-- convert the result to kilometers if desired
IF measure = 'Kilometers' THEN
SET distInSelectedUnit = MilesToKilometers(distInSelectedUnit);
END IF;
RETURN distInSelectedUnit;
END
Es nimmt originLatitude, originLongitude, relativeLatitude, relativeLongitude und measure als Parameter. Das Maß kann einfach Miles sein oder Kilometers
Hoffe das hilft!
