What's a core?
"A core is an area or patch of relatively intact habitat that is sufficiently large to support more than
one individual of a species" (Firehock and Walker, 1015).
For our purposes that's an area at least 100 acres in size and at least 200 meters wide.
How did we make them?
We assembled and used nationally available databases and implemented a methodology using ArcGIS
toolboxes and configuration files, published by the
Green Infrastructure Center, Inc.
For the initial definition of cores, the most important dataset was the National Landcover Database 2011.
Using it we considered intact habitat to be any landcover class that was not "a developed area" or
agriculture. Agriculture is an important element of Green Infrastructure planning, be we don't consider
it existing natural habitat.