module RingArea

Extended Modules

Defined in:

ring_area.cr
ring_area/area.cr

Constant Summary

EARTH_RADIUS = 6371008.8
FACTOR = (EARTH_RADIUS * EARTH_RADIUS) / 2

A constant factor used to compute the area of a polygon. It's derived from the square of the Earth's radius divided by 2.

FACTORS = {acres: 0.000247105, centimeters: 10000, centimetres: 10000, feet: 10.763910417, hectares: 0.0001, inches: 1550.003100006, kilometers: 0.000001, kilometres: 0.000001, meters: 1, metres: 1, miles: 3.86e-7, nauticalmiles: 2.9155334959812285e-7, millimeters: 1000000, millimetres: 1000000, yards: 1.195990046}
PI_OVER_180 = Math::PI / 180

A constant used for converting degrees to radians. Represents the ratio of PI to 180.

VERSION = {{ (`shards version /srv/crystaldoc.info/github-geocrystal-ring_area-v0.2.1/src`).chomp.stringify }}

Instance Method Summary

Instance Method Detail

def ring_area(coords : Array(Array(Number))) : RingArea::Area #

Calculate the approximate area of the polygon were it projected onto the earth.

Reference: Robert. G. Chamberlain and William H. Duquette, "Some Algorithms for Polygons on a Sphere", JPL Publication 07-03, Jet Propulsion Laboratory, Pasadena, CA, June 2007 https://trs.jpl.nasa.gov/handle/2014/40409

coords - Ring Coordinates as [[longitude1, latitude1], [longitude2, latitude2], ...]

Return the approximate geodesic area of the polygon.

https://github.com/Turfjs/turf/blob/master/packages/turf-area/index.ts


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