docs: function determineGroundResolution(res) {
    
    //iterate over all resolutions
    for (let int = 0; int < res.length; int++) {
      let r = res[int];
  
      //calculate the resolution if not available
      if (!r.groundResolution) {
        r.groundResolution = (0.0254 * r.scale) / r.dpi;
      }
    }
  
  }