GeoCircle

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`GeoCircle`

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GeoCircle[loc,r]

is a two-dimensional GeoGraphics primitive that represents a circle of radius r centered at the location loc on the surface of the Earth.

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GeoCircle[loc,r,{α₁,α₂}]

represents a sector of a circle from bearing α₁ to bearing α₂.

Details

A geo circle with center loc and radius r is defined as the endpoints of all geodesics of length r starting from loc. Specifying bearings α₁ and α₂ restricts the set of geodesics.
The location loc can be specified either as latitude and longitude coordinates {lat,lon} in degrees, GeoPosition[…], or as a named geographical Entity[…].
The radius r can be given as a Quantity length or as a number in meters.
Bearings α₁ and α₂ are measured clockwise from true north and can be given as Quantity angles, as numbers in degrees, as DMS strings, or as named compass points like "N" or "SouthWest".
GeoCircle[loc] represents a geo circle centered at loc, with an automatic choice of radius.
GeoCircle[] is equivalent to GeoCircle[$GeoLocation].

Examples

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Basic Examples (2)Summary of the most common use cases

A circle of 3000 kilometers around a geo location:

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https://wolfram.com/xid/0tz1mi9e-bsh72e

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A sector of a circle over South America:

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https://wolfram.com/xid/0tz1mi9e-5t1541

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https://wolfram.com/xid/0tz1mi9e-tuvfqh

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Scope (6)Survey of the scope of standard use cases

The center location of the geo circle can be specified in several ways:

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https://wolfram.com/xid/0tz1mi9e-8hqw6y

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https://wolfram.com/xid/0tz1mi9e-8fh7rr

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The default location is the local geo position:

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https://wolfram.com/xid/0tz1mi9e-5kh819

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https://wolfram.com/xid/0tz1mi9e-z9s0ni

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The geo circle radius can be specified as a Quantity object or directly in meters:

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https://wolfram.com/xid/0tz1mi9e-i2e0ab

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The default radius is computed automatically:

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https://wolfram.com/xid/0tz1mi9e-4l8yop

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Bearings are given in degrees, clockwise with respect to true north:

In[1]:=1

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https://wolfram.com/xid/0tz1mi9e-56far4

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In[2]:=2

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https://wolfram.com/xid/0tz1mi9e-nhacni

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Use different styles for geo circles:

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https://wolfram.com/xid/0tz1mi9e-e8suiu

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Applications (2)Sample problems that can be solved with this function

Illustrate projection effects by same-area circles:

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https://wolfram.com/xid/0tz1mi9e-77g8hp

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Use GeoCircle objects as segments in a FilledCurve region:

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https://wolfram.com/xid/0tz1mi9e-q5wzac

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Properties & Relations (7)Properties of the function, and connections to other functions

A geo circle is the set of points whose distance to the center is the radius:

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https://wolfram.com/xid/0tz1mi9e-1oa0pq

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https://wolfram.com/xid/0tz1mi9e-mkuypz

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The interior of a geo circle is a geo disk:

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https://wolfram.com/xid/0tz1mi9e-ydlvuh

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https://wolfram.com/xid/0tz1mi9e-hlspt4

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A GeoCircle object is described using coordinates and distances on the Earth, irrespective of the coordinates used in the final map. A Circle object is described using the coordinates of the final map:

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https://wolfram.com/xid/0tz1mi9e-bez1gv

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It is possible to use a GeoPosition object to specify the center of the Circle object. Its radius, however, cannot be specified as a length on the surface of the Earth:

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