Use this cartographic calculation to convert, scale, or compare map, terrain, bearing, raster, or route quantities when the coordinate and unit conventions are explicitly known.

Height Meters (m)

Required number input.

Earth Radius Kilometers (km)

Required number input.

Geometric horizon distance in kilometres for observer height and spherical Earth radius, without refraction. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Horizon Kilometers (km)

The resulting horizon kilometers returned as a number.

• Map calculations depend on datum, projection, latitude, scale definition, magnetic-declination epoch, and whether distances are planar, rhumb-line, or geodesic. A compact formula cannot remove distortion or infer the missing reference system.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Confirm the map datum, projection, scale, and bearing convention before applying the result. Use geodesic or GIS software with current reference data when survey-grade or navigation-critical accuracy is required.

• Haversine Distance Cartography

  Spherical great-circle distance in kilometres using a user-supplied Earth radius.

• Latitude Degree To Km Fixed

  Approximate north-south kilometres per latitude degree on a spherical Earth.

• Longitude Degree To Km Departure

  Approximate east-west kilometres per longitude degree at latitude on a spherical Earth.