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geo.ellipsePolygon

geo.ellipsePolygon(
   $center as cts.point,
   $semi-major-axis as Number,
   $semi-minor-axis as Number,
   $azimuth as Number,
   $arc-tolerance as Number,
   [$options as String[]]
) as cts.region

Summary

Construct a polygon that approximates an ellipse.

Parameters
$center Center of the ellipse.
$semi-major-axis The semi major axis of the ellipse, in the same units of measure as specified in the units option.
$semi-minor-axis The semi minor axis of the ellipse, in the same units of measure as specified in the units option.
$azimuth The azimuth.
$arc-tolerance How far the approximation can be from the actual ellipse, specified in the same units as the units option. Arc-tolerance should be greater than the value of the tolerance option, which defaults to 0.3106856 miles.
$options Options with which to customize this operation. The following options are available:
"coordinate-system=string"
Use the given coordinate system. Valid values are:
wgs84
The WGS84 coordinate system.
raw
The raw (unmapped) coordinate system.
"tolerance=value"
A tolerance value. For the raw coordinate system, use the units of the coordinate system. For other (geodetic) coordinate systems, use the units specified by the units option. If the tolerance is too fine for the precision, inconsistencies may result and a larger tolerance should be used. Tolerance cannot be zero. Default: 0.3106856 miles (0.05 km).
"units=miles"
Distance is measured in miles.

Usage Notes

When approximating the polygon, if the distance between two points is less than tolerance, then they are considered to be the same point. The arc-tolerance parameter specifies the allowable error in the polygon approximation. That is, the resulting polygon will differ from the provided ellipse by at most arc-tolerance.

The arc-tolerance parameter value should be greater than the tolerance, and both arc-tolerance and tolerance should be expressed in the same units. Use the tolerance option to override the default tolerance value.

Example

geo.ellipsePolygon(cts.point(1,1),4,2,math.pi() / 2.0,1,['tolerance=0.1'])

// => A cts:region with the following coordinates:
//    1,1.0582174 0.97955137,1.0411657 0.97108173,0.99999946
//    0.97955191,0.95883381 1,0.94178247 1.0204481,0.95883381
//    1.0289183,0.99999946 1.0204486,1.0411657 1,1.0582174

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