How Airports Serve Maryland
Mark Pearson
This map displays the major airports in and around Maryland. It shows how the state can divided according to which airport is the closest as the crow flies.
The flags are a sample of 500 census tracts (of 1390 tracts total) within the state.
Some census tract flags may look like they are colored for one airport's region but are actually in another airport's region. The census tract flags are colored with which airport they are closest to as the crow flies along the surface of the earth (the Haversine distance formula). The region boundaries that are displayed on map were computed assuming assuming the earth is flat. (The lines that divide regions are a Voronoi diagram, and I couldn't find any algorithm that calculate the lines on a sphere such as the earth.) In short, although a few census tracts may look like they're mislabeled near a boundary, it's actually the boundary that is slightly wrong.
For more information, see the full report:
http://www.mark-pearson.com/airport-distances/

BWI serves 2,933,794 people in MD
Baltimore/Washington International Thurgood Marshall Airport

DCA serves 1,670,950 people in MD
Ronald Reagan Washington National Airport

IAD serves 752,388 people in MD
Washington Dulles International Airport

SBY serves 264,350 people in MD
Salisbury-Ocean City Wicomico Regional Airport

PHL serves 76,414 people in MD
Philadelphia International Airport

PIT serves 44,060 people in MD
Pittsburgh International Airport

MDT serves 31,596 people in MD
Harrisburg International Airport

dividing line

5,192 people
closest airport: DCA

1,966 people
closest airport: DCA

5,142 people
closest airport: IAD

closest airport: BWI

closest airport: IAD

closest airport: DCA

closest airport: SBY

closest airport: PHL

18 people

closest airport: PIT

977 people