How Airports Serve Wisconsin
Mark Pearson
This map displays the major airports in and around Wisconsin. 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 1392 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/

MKE serves 2,050,413 people in WI
General Mitchell International Airport

MSN serves 1,083,614 people in WI
Dane County Regional Airport (Truax Field)

ATW serves 671,718 people in WI
Outagamie County Regional Airport

CWA serves 541,060 people in WI
Central Wisconsin Airport

GRB serves 503,611 people in WI
Austin Straubel International Airport

LSE serves 442,610 people in WI
La Crosse Municipal Airport

MSP serves 258,148 people in WI
Minneapolis-St. Paul International Airport (Wold-Chamberlain Field)

DLH serves 122,316 people in WI
Duluth International Airport

RST serves 9,632 people in WI
Rochester International Airport

CID serves 3,864 people in WI
The Eastern Iowa Airport

dividing line

2,477 people
closest airport: MKE

7,996 people
closest airport: CWA

3,950 people
closest airport: MSN

closest airport: MKE

closest airport: LSE

closest airport: CWA

closest airport: MSN

closest airport: GRB

closest airport: ATW

closest airport: DLH

closest airport: MSP

727 people