title: Stack drone images in IDL_overlap degree
body: <p>I have about 6000 aerial images taken by 3DR drone for vegetation sites.</p>
  
  <p>The images have to overlap to some extant because the drone flights cover the area go from EW and then again NS, so the images present the same area from two directions. I need the overlap for the images for extra accuracy. </p>
  
  <p>I don't know to write a code on IDL to combine the images and create that overlap. Can anyone help please?</p>
  
  <p>Thanks</p>