How to convert Android GPS coordinates into X,Y coordinates.
Without further math bullshit about all the conversion systems, when you have a bunch of Android GPS coordinates (which are compatible with Google Earth and Google Maps), and you want to draw them on a finite 2D plane, here’s what worked for me.
int x = (int) ((PLANE_WIDTH/360.0) * (180 + lon)); int y = (int) ((PLANE_HEIGHT/180.0) * (90 - lat));
January 7th, 2011 at 7:03 am
Im trying your algorithm but I cannot put this working yet, as the GPS coordinates are in double, when I cast the X and Y to int Im losing information and the integer value remain almost the same….Im putting the PLANE_WIDTH and PLANE_HEIGHT with the resolution of my screen device 320×480, like PLANE_WIDTH=320 and PLANE_HEIGHT=480 . Any tip are more than welcome?
Here is my code:
public void convertGPStoCartezian(double longitude, double latitude){
int x = (int) ((320/360.0) * (180 + longitude));
int y = (int) ((480/180.0) * (90 – latitude));
}
Cheers
Joao
February 14th, 2011 at 5:27 pm
Yes, there will be loss of precision, this formula is not the best if you’re looking for too much accuracy, but it’s great to visualize a lot of data. It does not account for the curvature of the earth.
If you want something more precise maybe you want to take a look at this
http://www.progonos.com/furuti/MapProj/Dither/CartHow/HowER_W12/howER_W12.html#DeductionEquirectangular