Distance Calculations in Android?

Question

I am very new to android Google maps i write the code for find distance between two places:

private String getDistance(final String start, final String end) {

           new Thread(new Runnable() {
                @Override
                public void run() {
     float distance = 0.0f;
               StringBuffer url = new StringBuffer("http://maps.googleapis.com/maps/api/directions/json?origin=");
                 url.append(start.replace(" ", "").trim().toString());
                 url.append("&destination=");
                 url.append(end.replace(" ", "").trim().toString());
                 url.append("&mode=transit");
                 url.append("&language=en-EN");
                 url.append("&sensor=false");



                 DefaultHttpClient httpClient = new DefaultHttpClient();
                 HttpGet httpGet = new HttpGet(url.toString());
                 HttpResponse httpResponse = httpClient.execute(httpGet);
                 HttpEntity httpEntity = httpResponse.getEntity();
                 String line = EntityUtils.toString(httpEntity);

                 JSONObject jsonObject = new JSONObject(line);
                 JSONArray jsonarray = jsonObject.getJSONArray("routes").getJSONObject(0).getJSONArray("legs");

                 for (int i = 0; i < jsonarray.length(); i++) {
                     JSONObject obj = jsonarray.getJSONObject(i);
                     distance  = Float.valueOf(obj.getJSONObject("distance").getString("text").replace("km", ""));
                     System.out.println("Distance == " + obj.getJSONObject("distance").getString("text").replace("km", ""));
                 }


              BigDecimal   kmVal = BigDecimal.valueOf(distance);
              System.out.println("===========distance=============="+kmVal);

            } catch (Exception e) {
                e.printStackTrace();
            }
                }
                }).start();

            return distance  ;

    }

I am getting the Distance with differences of 30 km. I am getting 30 km extra instead of actual distance.

The first thing you should do is separate out the different responsibilities in your code...fetching the data and calculating distance should be separate concerns. Then try running in the debugger — Mitch Wheat, Nov 05 '12 at 08:33
by breaking the problem down, and debugging...like I just mentioned... — Mitch Wheat, Nov 05 '12 at 08:36
my concern is i am getting distance in km but with 30k extara distance? — user1787493, Nov 05 '12 at 08:38
So separate the code into two methods. One to get the data and one to calculate the distance then debug. Just like Mitch says. — Simon, Nov 05 '12 at 08:39
you need to learn about threads, first. Why do you use a Thread, what do you expect will happen with your program, what does final mean, and then, what is the actual distance, how do you know the output is wrong ... — njzk2, Nov 05 '12 at 08:39
While we are raising concerns, I have one too. What's up with asking the same question, not once, not twice, but counting this one, **4 times**? [First](http://stackoverflow.com/q/13206451/450534), [Second](http://stackoverflow.com/q/13208501/450534) and [Third](http://stackoverflow.com/q/13208946/450534). They all seem to be different, but essentially, for the same purpose. — Siddharth Lele, Nov 05 '12 at 09:12

score 1 · Answer 1 · edited May 23 '17 at 10:25

1

Try this links it will Defiantly helps you.

edited May 23 '17 at 10:25

Community

1
1

answered Nov 05 '12 at 08:38

Chintan Khetiya

15,962
9
47
85

score 0 · Answer 2 · answered Nov 05 '12 at 08:41

0

You don't have to query the google maps to get the distance between two places. If you know the latitude and longitude of both places you can just construct Location objects and use it's distanceTo() method which will give you the exact distance in meters.

Location from = new Location("");
from.setLatitude(yourStartLatitude);
from.setLongitude(yourStartLongitude);

Location to = new Location("");
to.setLatitude(yourEndLatitude);
to.setLongitude(yourEndLongitude);

float distance = from.distanceTo(to); // The distance in meters

answered Nov 05 '12 at 08:41

Adam Monos

4,287
1
23
25

by this i am getting 514625.25 these type of values i am getting ? – user1787493 Nov 05 '12 at 08:56
that means 514625 m = 514,6 km – Adam Monos Nov 05 '12 at 08:59
that is not actual distance suppose hyderabad to chennai is 620km but based on this wrong? – user1787493 Nov 05 '12 at 09:06
This is the distance in a straight line, not on roads. If that's what you are after, you shouldn't use this method. If you just want to know the exact distance, then this is it. – Adam Monos Nov 05 '12 at 09:09
ok thanks for your help by this http://maps.googleapis.com/maps/api/distancematrix/json?origins= – user1787493 Nov 05 '12 at 09:15
getting the exact distance how can i use in my requirement ? – user1787493 Nov 05 '12 at 09:16
To be picky, the distance returned is along a great circle, not a straight line. – Simon Nov 05 '12 at 09:21
is there another possibility to find distance using alt and lang positions ? – user1787493 Nov 05 '12 at 09:24

Distance Calculations in Android?

2 Answers2