transforming geolocation coordinates to relative units ... dummy template

template

var loc = [
  { x : 3,
    y : 3,
    gx : 8,
    gy : 8 
  }, 
  { x : 6,
    y : 6,
    gx : 12,
    gy : 12 
  }
],
ratio = {}, 
base = {};

ratio.x = (loc[0].gx - loc[1].gx) / (loc[0].x - loc[1].x);
ratio.y = (loc[0].gy - loc[1].gy) / (loc[0].y - loc[1].y);
base.x = loc[0].gx - loc[0].x * ratio.x;
base.y = loc[0].gy - loc[0].y * ratio.y;

loc[2] = {
  gx : 15,
  gy : 15
};
loc[2].x = (loc[2].gx - base.x) / ratio.x;
loc[2].y = (loc[2].gy - base.y) / ratio.y;