How do I remove the collar from overlapping imagery files?
If the collar surrounding your imagery files is either black or white (or very close to one of those colors), you can use either the Darken or Lighten blend mode functionality in Global Mapper to remove the collars. To setup the blend modes, open the Control Center (found on the toolbar and under the Tools menu), highlight the imagery layers that you want to remove the collar from, and select the Options button. If the color is black, select the Lighten blend mode from the Blend Mode drop-down list. If the collar color is white, select the Darken blend mode. Then press OK. Finally, you’ll also need to set the background color of the Global Mapper view to be either black or white to match the collar color so that the non-overlapping regions aren’t affected. You can change the background color under the View menu.