Mapping Toolbox

Measuring Distance

When you calculate the distance between two points with the Mapping Toolbox, the result will depend upon whether you want a great circle or a rhumb line distance. The distance command will return the appropriate distance between two points as an angular arc length, employing the same angular units as the input latitudes and longitudes. The default path type is the shorter great circle, and the default angular units are degrees. The previous figure shows two points at (15°S, 0°) and (60°N, 150°E). The great circle distance between them, in degrees of arc, is as follows:

• distgc = distance(-15,0,60,150)
  distgc =
      129.9712
  

The rhumb line distance is greater:

• distrh = distance('rh',-15,0,60,150)
  distrh =
      145.0288
  

To determine how much longer the rhumb line path is in, say, kilometers, you can use a distance conversion function on the difference:

• kmdifference = deg2km(distrh-distgc)
  kmdifference =
      1.6744e+03
  

Several distance conversion functions are available in the toolbox, supporting degrees, radians, kilometers, meters, statute miles, nautical miles, and feet. Converting distances between angular arc length units and surface length units requires the radius of a planet or spheroid. By default, the radius of the Earth is used.

Great Circles and Rhumb Lines

Measuring Azimuth and Elevation