I'm working in max/msp where you have patches and you can connect lines between objects to program (so no typing). The program is used the most to work with sound.

I receive gps data from my phone in max and i need to calculate distance. First it did this in processing cause that's far more easy. The distances i calculate are quite small (it's for walking).
In my calculation from my pc to the kitchen, dLat is -1.3315805E-7 and dLon is 1.7476995E-7 for example.
Which is something like 0.000000017476995 if i'm correct.

Is there a way to make it more precise?

1. /*
2. //pc
3.  testP: gps 5.910325 30. 51.988632 57. 28.372467
4.  
5.  //keuken
6.  testP: gps 5.91006 10. 51.988777 19. 29.984245
7.  */
8. void setup() {
9.   // println(getDistance(51.988632, 5.910325, 51.988777, 5.91006)); // pc > keuken
10.   // println(getDistance(51.988777, 5.910006, 51.988739, 5.910056));
11. /*
12.   String[] lines = loadStrings("geo.tsv");
13.   String[] tokens = split(lines[0], "\t");
14.   float lon1 = float(tokens[2]);
15.   float lat1 =  float(tokens[4]);
16.   for (int i = 1; i < 2; i++) { //lines.length-1
17.     tokens = split(lines[i+1], "\t");
18.     float lon2 = float(tokens[2]);
19.     float lat2 =  float(tokens[4]);
20.     //println(lat2+"\t"+lon2);
21.     float d = getDistance(lon1, lat1, lon2, lat2);
22.     println(d*1000);
23.   }
24.   */
25.   float d = getDistance(5.910161, 51.988705, 5.910171, 51.988697);
26.   println(d*1000);
27.  
28. }
29. float getDistance(float lon1, float lat1, float lon2, float lat2) {
30.   int R = 6371; // Radius of the earth in km
31.   float dLat = radians(lat2-lat1);
32.   float dLon = radians(lon2-lon1);
33.  
34.   println("dLat: "+dLat+"\ndLon: "+dLon);
35.   float a = sin(dLat/2) * sin(dLat/2) + cos(radians(lat1)) * cos(radians(lat2)) * sin(dLon/2) * sin(dLon/2);
36.   float c = 2 * atan2(sqrt(a), sqrt(1-a));
37.   float d = R * c; // Distance in km
38.   return d;
39. }