Creating and Editing Overlay Files

note Creating and editing overlay files should be done only under the supervision of the system manager.
  1. Use a computerized geographic database to get the array of coastlines and political boundaries you want.
  2. Manually add the header commands, display it with overlay and make needed repairs.
  3. Add the desired text and icon features.
  4. Add underlay fill points. When doing this you may discover more breaks in the overlay lines which need to be repaired.
  5. Test the underlay filling by displaying over a broad range of image sizes, for example 50, 100, 200, 400, and 800 km (31.1, 62.1, 124.3, 248.5, 497.1 mi). It is usually necessary to add fill points in lakes and bays pointing towards the display center.
  6. When you are satisfied with your overlay, place it in the $IRIS_OVERLAY directory.