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This question already has an answer here:

What is the Quickest method for determining which postcode is 2 miles north of original postcode?

For instant L17.

I know how to determine the distance between 2 points as below, but the above formulae eludes me.

Code:

    public static final double PI = 3.14159265;
    public static final double deg2radians = PI/180.0;

    double lat1 = latitude1  * deg2radians;
    double lat2 = latitude2  * deg2radians;
    double lon1 = longitude1 * deg2radians;
    double lon2 = longitude2 * deg2radians;

    radd=2*Math.asin(Math.sqrt(Math.pow(Math.sin((lat1-lat2)/2),2.0) +
                  Math.cos(lat1)*Math.cos(lat2)*Math.pow(Math.sin((lon1-lon2)/2)
,2.0)));

marked as duplicate by whuber Mar 7 '14 at 14:51

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  • From what I understand, UK postcodes are not geometrically determined. – mkennedy Mar 6 '14 at 21:45
  • That may be the case (which I don't know) but we can convert British postcodes into Longitude and latitudes which is how mapping software works – user27768 Mar 6 '14 at 21:46
  • 1
    Oh, thank you. You're looking for either the geodesic 'forward' algorithm or its great circle equivalent. – mkennedy Mar 6 '14 at 21:50
  • How do those work in relation to the above? Do you mind giving an example :-) thanks – user27768 Mar 6 '14 at 22:09
  • Finally found a related gis.SE question: gis.stackexchange.com/questions/5821/… – mkennedy Mar 6 '14 at 22:43