Map tiling - What kind of projection?
- by ikky
Hi.
I've taken a large image and divided it in to square tiles (256x256). It is made for google maps also, so the whole image is divided into z_x_y.png (Depending on zoom level).
z=0 = 1x1 tile
z=1 = 2x2 tilesthe
z=2 = 4x4 tiles
My imageMap is "flat" and is not based on a sphere like the worldmap.
I'm gonna use this map on a windows mobile app (which has no google API), and all the "points of interests" is inserted into a database by longitude and latitude. And since i have to make this for the windows mobile, i just have XY coordinate system.
Is it enough to just use this:
MAP_WIDTH = 256*TILES_W;
MAP_HEIGHT = 256*TILES_H;
function convert(int lat, int lon)
{
int y = (int)((-1 * lat) + 90) * (MAP_HEIGHT / 180);
int x = (int)(lon + 180) * (MAP_WIDTH / 360);
ImagePoint p = new ImagePoint(x,y); // An object which holds the coordinates
return p;
}
Or do i need a projection technique?
Thanks in advance.
Please ask, if something is unclear.