GeoHemisphereBoundary

GeoHemisphereBoundary[]

is a one-dimensional GeoGraphics primitive that represents the boundary line of a hemisphere of the Earth centered at the current geo location.

GeoHemisphereBoundary[loc]

represents the boundary line of a hemisphere centered at the location loc.

Details

  • The boundary of a hemisphere is a line contained on a plane that goes through the center of the Earth. Hence this line is a great ellipse.
  • The location loc can be specified as latitude and longitude coordinates {lat,lon} in degrees, as GeoPosition[{lat, lon}], or as named entities Entity[].

Examples

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Basic Examples  (2)

The boundary of the hemisphere around the current geo location:

The boundary of the hemisphere centered at Buenos Aires, in the Albers projection:

Scope  (2)

The boundary of the hemisphere around your current geo location:

The boundary of the hemisphere around a particular location, specified in several possible ways:

Properties & Relations  (4)

GeoHemisphereBoundary[loc] is the boundary of GeoHemisphere[loc]:

DayNightTerminator[date] is equivalent to GeoHemisphereBoundary[loc] for the location having the Sun at its zenith at the given date:

This is the geo location that has the Sun at its zenith at that moment:

GeoHemisphereBoundary always represents a great ellipse:

Select some points on the hemisphere boundary and construct great ellipse segments among them:

These two curves exactly coincide:

The hemisphere boundary does not coincide, however, with geodesic or rhumb line segments:

Due to the small eccentricity of the Earth, the geodesic segments approach the great ellipse quite well:

GeoHemisphereBoundary is the limit of infinite height of GeoVisibleRegionBoundary:

Introduced in 2015
 (10.1)