Calculate distance between 2 GPS coordinates

Question

How do I calculate distance between two GPS coordinates (using latitude and longitude)?

Answer 1

I needed to implement this in PowerShell, hope it can help someone else. Some notes about this method

1. Don't split any of the lines or the calculation will be wrong
2. To calculate in KM remove the * 1000 in the calculation of $distance
3. Change $earthsRadius = 3963.19059 and remove * 1000 in the calculation of $distance the to calulate the distance in miles

4. I'm using Haversine, as other posts have pointed out Vincenty's formulae is much more accurate

   Function MetresDistanceBetweenTwoGPSCoordinates($latitude1, $longitude1, $latitude2, $longitude2)  
   {  
     $Rad = ([math]::PI / 180);  
   
     $earthsRadius = 6378.1370 # Earth's Radius in KM  
     $dLat = ($latitude2 - $latitude1) * $Rad  
     $dLon = ($longitude2 - $longitude1) * $Rad  
     $latitude1 = $latitude1 * $Rad  
     $latitude2 = $latitude2 * $Rad  
   
     $a = [math]::Sin($dLat / 2) * [math]::Sin($dLat / 2) + [math]::Sin($dLon / 2) * [math]::Sin($dLon / 2) * [math]::Cos($latitude1) * [math]::Cos($latitude2)  
     $c = 2 * [math]::ATan2([math]::Sqrt($a), [math]::Sqrt(1-$a))  
   
     $distance = [math]::Round($earthsRadius * $c * 1000, 0) #Multiple by 1000 to get metres  
   
     Return $distance  
   }