Python – Getting distance between two points based on latitude/longitude

geogeocodinggeographypython

I tried implementing this formula: http://andrew.hedges.name/experiments/haversine/
The aplet does good for the two points I am testing:

enter image description here

Yet my code is not working.

from math import sin, cos, sqrt, atan2

R = 6373.0

lat1 = 52.2296756
lon1 = 21.0122287
lat2 = 52.406374
lon2 = 16.9251681

dlon = lon2 - lon1
dlat = lat2 - lat1
a = (sin(dlat/2))**2 + cos(lat1) * cos(lat2) * (sin(dlon/2))**2
c = 2 * atan2(sqrt(a), sqrt(1-a))
distance = R * c

print "Result", distance
print "Should be", 278.546

The distance it returns is 5447.05546147. Why?

Best Answer

Update: 04/2018: Vincenty distance is deprecated since GeoPy version 1.13 - you should use geopy.distance.distance() instead!

The answers above are based on the Haversine formula, which assumes the earth is a sphere, which results in errors of up to about 0.5% (according to help(geopy.distance)). Vincenty distance uses more accurate ellipsoidal models such as WGS-84, and is implemented in geopy. For example,

import geopy.distance

coords_1 = (52.2296756, 21.0122287)
coords_2 = (52.406374, 16.9251681)

print geopy.distance.vincenty(coords_1, coords_2).km

will print the distance of 279.352901604 kilometers using the default ellipsoid WGS-84. (You can also choose .miles or one of several other distance units).

Related Solutions

Java – How to measure distance and create a bounding box based on two latitude+longitude points in Java

Here is a Java implementation of Haversine formula. I use this in a project to calculate distance in miles between lat/longs.

public static double distFrom(double lat1, double lng1, double lat2, double lng2) {
    double earthRadius = 3958.75; // miles (or 6371.0 kilometers)
    double dLat = Math.toRadians(lat2-lat1);
    double dLng = Math.toRadians(lng2-lng1);
    double sindLat = Math.sin(dLat / 2);
    double sindLng = Math.sin(dLng / 2);
    double a = Math.pow(sindLat, 2) + Math.pow(sindLng, 2)
            * Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2));
    double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
    double dist = earthRadius * c;

    return dist;
    }

Calculate distance between 2 GPS coordinates

Calculate the distance between two coordinates by latitude and longitude, including a Javascript implementation.

West and South locations are negative. Remember minutes and seconds are out of 60 so S31 30' is -31.50 degrees.

Don't forget to convert degrees to radians. Many languages have this function. Or its a simple calculation: radians = degrees * PI / 180.

function degreesToRadians(degrees) {
  return degrees * Math.PI / 180;
}

function distanceInKmBetweenEarthCoordinates(lat1, lon1, lat2, lon2) {
  var earthRadiusKm = 6371;

  var dLat = degreesToRadians(lat2-lat1);
  var dLon = degreesToRadians(lon2-lon1);

  lat1 = degreesToRadians(lat1);
  lat2 = degreesToRadians(lat2);

  var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
          Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2); 
  var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
  return earthRadiusKm * c;
}

Here are some examples of usage:

distanceInKmBetweenEarthCoordinates(0,0,0,0)  // Distance between same 
                                              // points should be 0
0

distanceInKmBetweenEarthCoordinates(51.5, 0, 38.8, -77.1) // From London
                                                          // to Arlington
5918.185064088764

Best Answer

Related Solutions

Java – How to measure distance and create a bounding box based on two latitude+longitude points in Java

Calculate distance between 2 GPS coordinates

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