title: Converting Longitude & Latitude to X Y on a map with Calibration points
body: <p>If i have a jpeg map with size sizeX, sizeY</p>
  
  <p>and some calibration points on the map (X, Y, Lon, Lat)</p>
  
  <p>What would be the algorithm for calculating the corresponding XY point in the map with a given Longitude / Latitude pair?</p>