# Android QuestionGPS - How to calculate the distance among two points

#### SamuelSlf

##### Member
Longtime User
Hello!

I need calculate distance among two points, how i make this?

Can be using the API of Google Maps or GPS.

Thanks!

#### James Chamblin

##### Active Member
Longtime User
You can use Location in the GPS library
B4X:
``````    Dim p1, p2 As Location
p1.Initialize2("+35.54569","-71.62213")
p2.Initialize2("+35.53427","-71.61508")
Dim Distance As Float = p1.DistanceTo(p2)
Log("Distance is "&Distance&" meters")``````

Longtime User
Thanks James!!

#### samperizal

##### Active Member
Longtime User
function in javascript but easy to transport.

function distance(lat1,lon1,lat2,lon2) {
var R = 6371; // km (change this constant to get miles)
var dLat = (lat2-lat1) * Math.PI / 180;
var dLon = (lon2-lon1) * Math.PI / 180;
var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
Math.cos(lat1 * Math.PI / 180 ) * Math.cos(lat2 * Math.PI / 180 ) *
Math.sin(dLon/2) * Math.sin(dLon/2);
var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
var d = R * c;
if (d>1) return Math.round(d)+"km";
else if (d<=1) return Math.round(d*1000)+"m";
return d;
}

#### klaus

##### Expert
Longtime User
The function above is less precise than the DistanceTo method from the GPS library.
Have a look at this thread Measurement of Distances.

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