Get gps location of a photo

问题:

I know how to get the current GPS location of a mobile phone. I also know how to save the GPS location to the photo when you take it. (Camera option Samsung galaxy s2).

But how can I get the GPS location of that photo (later)? When I open the photo on the computer, I can see the GPS location data, but got no idea how to extract them later in android. So could someone put me in the good direction? To make question more clearly: How can I get the GPS location of a photo that is already taken?

Thanks already, Bigflow

回答1:

josnidhin made this answer possible, so be sure to give him credit too :)

Here we go:

import android.media.ExifInterface;

exif = new ExifInterface(filePath);
String lat = ExifInterface.TAG_GPS_LATITUDE;
String lat_data = exif.getAttribute(lat);

After that, lat_data will be something like: 51/1,58/1,32/1

This is the same as: 51, 58, 32. (typing this in google maps will give bad result)

To get the gps coordinates of this you need to do some math, here it comes:

1. Calculate the total number of seconds:
   58′32″ = (58*60 + 32) = 3512 seconds.
2. The fractional part is total number of seconds divided by 3600:
   3512 / 3600 = ~0.975556
3. Add fractional degrees to whole degrees to produce the final result:
   51 + 0.975556 = 51.975556
4. If it is a West longitude coordinate, negate the result. (it isn't this time)
5. answer: 51.975556

This is also the same when you with TAG_GPS_LONGITUDE

回答2:

I think the geotag is in the EXIF data of the photo taken. Find a suitable EXIF data reader which will help you extract the data you want.