How Airports Serve Idaho
Mark Pearson
This map displays the major airports in and around Idaho. It shows how the state can divided according to which airport is the closest as the crow flies.
The flags are a sample of 298 census tracts (of 298 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/

BOI serves 831,248 people in ID
Boise Airport (Boise Air Terminal) (Gowen Field)

IDA serves 390,053 people in ID
Idaho Falls Regional Airport (Fanning Field)

GEG serves 293,253 people in ID
Spokane International Airport (Geiger Field)

MSO serves 22,933 people in ID
Missoula International Airport

SLC serves 12,786 people in ID
Salt Lake City International Airport

JAC serves 11,662 people in ID
Jackson Hole Airport

GPI serves 5,647 people in ID
Glacier Park International Airport

dividing line

3,367 people
closest airport: GEG

7,394 people
closest airport: GEG

4,286 people
closest airport: IDA

closest airport: JAC

closest airport: BOI

closest airport: GEG

closest airport: IDA

closest airport: MSO

345 people

closest airport: SLC

closest airport: GPI

278 people

982 people