# GeoHemisphereBoundary

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

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)

is the boundary of GeoHemisphere[loc]:

DayNightTerminator[date] is equivalent to 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:

Wolfram Research (2015), GeoHemisphereBoundary, Wolfram Language function, https://reference.wolfram.com/language/ref/GeoHemisphereBoundary.html.

#### Text

Wolfram Research (2015), GeoHemisphereBoundary, Wolfram Language function, https://reference.wolfram.com/language/ref/GeoHemisphereBoundary.html.

#### CMS

Wolfram Language. 2015. "GeoHemisphereBoundary." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/GeoHemisphereBoundary.html.

#### APA

Wolfram Language. (2015). GeoHemisphereBoundary. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/GeoHemisphereBoundary.html

#### BibTeX

@misc{reference.wolfram_2024_geohemisphereboundary, author="Wolfram Research", title="{GeoHemisphereBoundary}", year="2015", howpublished="\url{https://reference.wolfram.com/language/ref/GeoHemisphereBoundary.html}", note=[Accessed: 21-June-2024 ]}

#### BibLaTeX

@online{reference.wolfram_2024_geohemisphereboundary, organization={Wolfram Research}, title={GeoHemisphereBoundary}, year={2015}, url={https://reference.wolfram.com/language/ref/GeoHemisphereBoundary.html}, note=[Accessed: 21-June-2024 ]}