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# Distance and Azimuths Between Two Sets of Coordinates Print Email

This function will calculate the distance and azimuth (referenced to True North) between two sets of coordinates on the Earth.  Bearings or azimuths start with 0 degrees toward true north, 90 degrees east, 180 degrees south, and 270 degrees west (clockwise rotation).

The terminal coordinates program can be used to find the coordinates at some distance, given an azimuth and the starting coordinates.

The shortest distance between two points on the surface of a sphere is an arc, not a line.  In addition, the azimuth looking from Point B to Point A will not be the converse (90 degrees minus the azimuth) of the azimuth looking from Point A to Point B.  (Try this using a string on a globe.)

Applicants will find this program helpful in determining compliance with the minimum spacing table in 47 CFR 73.207 for FM stations or 47 CFR 73.610 for television stations, or suitable allotment reference coordinates for FM commercial stations.  DXers (long distance listeners and viewers) may find this program useful to help determine how far away originating stations are, if the station's coordinates are known (try the AM Query, FM Query for radio broadcast stations in the United States, or TV Query for television stations).

##### Find Distance, Azimuths Between Two Points
Enter the Initial Coordinates in Degrees, Minutes, and Seconds:

Latitude      North    South
Longitude   West     East

Enter the Second Set of Coordinates in Degrees, Minutes, and Seconds:

Latitude      North    South
Longitude   West     East

Choose Method of Calculating Distance:

Distance per Sections 73.208 (FM) and 73.611 (TV)
( Valid out to a maximum distance of 475 km / 295 miles per Section 73.208(c) )

Distance per the Great Circle Method (AM)

Spacings per the 1992 U.S.- Mexican Agreement for FM Broadcasting
(FM in Mexican Border Zone only)

Note: For these last two methods of spacing determination,
latitude will be reset to N and longitude to W.

The original DIST program was written by John Boursy and modified in 1993 by Gary Kalagian.
Adapted for Internet use by Dale Bickel in December 1998.

Questions on Distance Between Coordinates may be directed to Dale Bickel, dale.bickel@fcc.gov.