# Documentation

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# Great Circles, Geodesics, and Rhumb Lines

Find the shortest path between two points; find the curve that crosses each meridian at the same angle

## Functions

 `azimuth` Azimuth between points on sphere or ellipsoid `departure` Departure of longitudes at specified latitudes `distance` Distance between points on sphere or ellipsoid `gc2sc` Center and radius of great circle `gcxgc` Intersection points for pairs of great circles `gcxsc` Intersection points for great and small circle pairs `meridianarc` Ellipsoidal distance along meridian `meridianfwd` Reckon position along meridian `reckon` Point at specified azimuth, range on sphere or ellipsoid `rhxrh` Intersection points for pairs of rhumb lines `track1` Geographic tracks from starting point, azimuth, and range `track2` Geographic tracks from starting and ending points `trackg` Great circle or rhumb line defined via mouse input `trackui` GUI to display great circles and rhumb lines on map axes

## Examples and How To

Calculate Intersection of Rhumb Line Tracks

This example shows how to calculate the intersection of rhumb lines using the `rhxrh` function.

Calculate Intersections of Arbitrary Vector Data

This example shows how to calculate the intersections of arbitrary vector data, such as polylines or polygons, using the `polyxpoly` function.

Calculate Distance Between Two Points in Geographic Space

Distance and azimuth are calculated from the position of two points in geometric space.

Calculate Azimuth and Elevation

Azimuth is the angle a line makes with a meridian, taken clockwise from north.

## Concepts

Great Circles

A great circle defines the shortest path between two points along the surface of a sphere.

Rhumb Lines

A rhumb line is a curve that crosses each meridian at the same angle.

Azimuth is the angle a line makes with a meridian, measured clockwise from north.

Positions, Azimuths, Headings, Distances, Length, and Ranges

Several angular and linear quantities express the distance between two points on a sphere.

Determine Destination Given Starting Point, Initial Azimuth, and Distance

Reckoning is the determination of a destination given a starting point, an initial azimuth, and a distance.

Calculate Distance Between Two Points in Geographic Space

Distance and azimuth are calculated from the position of two points in geometric space.