FInd latitude longitude point in php given initial lat lng, distance, and bearing

Question

In php, given a latitude and longitude point, a bearing (in degrees), and a distance (in feet or km or whatever) how do I figure out what the new lat lng point is? here is what I tried, but it's wrong. ``` function destinationPoint($lat, $lng, $brng, $dist) { $meters = $dist/3.2808399; // dist in meters $dist = $meters/1000; // dist in km $rad = 6371; // earths mean radius $dist = $dist/$rad; // convert dist to angular distance in radians $brng = deg2rad($brng); // conver to radians $lat1 = deg2rad($lat); $lon1 = deg2rad($lng); $lat2 = asin(sin($lat1)*cos($dist) + cos($lat1)*sin($dist)*cos($brng) ); $lon2 = $lon1 + atan2(sin($brng)*sin($dist)*cos($lat1),cos($dist)-sin($lat1)*sin($lat2)); $lon2 = ($lon2+3*M_PI) % (2*M_PI) - M_PI; // normalise to -180..+180º $lat2 = rad2deg($lat2); $lon2 = rad2deg($lon2); echo "lat2 = ".$lat2."
"; echo "lon2 = ".$lon2."
"; } ```

Accepted Answer

Just change

```
$lon2 = ($lon2+3*M_PI) % (2*M_PI) - M_PI;
```

to

```
$lon2 = fmod($lon2 + 3*M_PI, 2*M_PI) - M_PI;
```

According to PHP's documentation about the modulus operator (`%`),

Operands of modulus are converted to integers (by stripping the decimal part) before processing.

fmod "[r]eturns the floating point remainder (modulo) of the division of the arguments."

FInd latitude longitude point in php given initial lat lng, distance, and bearing

Solution

Problem