www.google.com/maps/d/edit?mid=1Vy4IWwOkljSV-GpvhrhNzxn9N9E0hJ8&usp=sharing zerg90 map of Chester County created December 1 2022
http://dsf.chesco.org/des/lib/des/fire_field_user_guide
http://dsf.chesco.org/des/lib/des/policefieldusers03.doc