DOQQ

This is a map showing DOQQ coverage of Michigan & Wisconsin. Each blue square represents areas where digital ortho photos have been completed by flying over and taking aerial photos.

http://http://www.lre.usace.army.mil/greatlakes/hh/greatlakestudies/lakemichiganpotentialdamagesstudy/gisanalyses/usacedetroitdistrictgisactivities/