s2-tools/dist/geometry/s2/cap.d.ts

A collection of geospatial tools primarily designed for WGS84, Web Mercator, and S2.

import type { S1Angle } from '../s1/angle';
import type { S1ChordAngle } from '../s1/chordAngle';
import type { Point3D, S2CellId, Vertices } from '../';
/**
 * S2Cap represents a disc-shaped region defined by a center and radius.
 * Technically this shape is called a "spherical cap" (rather than disc)
 * because it is not planar; the cap represents a portion of the sphere that
 * has been cut off by a plane.  The boundary of the cap is the circle defined
 * by the intersection of the sphere and the plane.  For containment purposes,
 * the cap is a closed set, i.e. it contains its boundary.
 *
 * For the most part, you can use a spherical cap wherever you would use a
 * disc in planar geometry.  The radius of the cap is measured along the
 * surface of the sphere (rather than the straight-line distance through the
 * interior).  Thus a cap of radius Pi/2 is a hemisphere, and a cap of radius
 * Pi covers the entire sphere.
 *
 * A cap can also be defined by its center point and height.  The height is
 * simply the distance from the center point to the cutoff plane.  There is
 * also support for empty and full caps, which contain no points and all
 * points respectively.
 *
 * This class is intended to be copied by value as desired.  It uses the
 * default copy constructor and assignment operator, however it is not a
 * "plain old datatype" (POD) because it has virtual functions.
 *
 * Here are some useful relationships between the cap height (h), the cap
 * radius (r), the maximum chord length from the cap's center (d), and the
 * radius of cap's base (a).
 *
 *     h = 1 - cos(r)
 *       = 2 * sin^2(r/2)
 *   d^2 = 2 * h
 *       = a^2 + h^2
 */
export interface S2Cap<T> {
    /** the center of the cap */
    center: Point3D;
    /** the radius of the cap */
    radius: S1ChordAngle;
    /** the data associated with the cap */
    data: T;
}
/**
 * Return an empty cap, i.e. a cap that contains no points.
 * @param data - the data
 * @returns - the empty cap
 */
export declare function emptyCap<T>(data: T): S2Cap<T>;
/**
 * Return a full cap, i.e. a cap that contains all points.
 * @param data - the data
 * @returns - the full cap
 */
export declare function fullCap<T>(data: T): S2Cap<T>;
/**
 * Return the area of the cap.
 * @param cap - the cap
 * @returns - the area
 */
export declare function getArea<T>(cap: S2Cap<T>): number;
/**
 * Return true if the cap is empty, i.e. it contains no points.
 * @param cap - the cap
 * @returns - true if the cap is empty
 */
export declare function isEmpty<T>(cap: S2Cap<T>): boolean;
/**
 * Return true if the cap is full, i.e. it contains all points.
 * @param cap - the cap
 * @returns - true if the cap is full
 */
export declare function isFull<T>(cap: S2Cap<T>): boolean;
/**
 * Returns the height of the cap, i.e. the distance from the center point to
 * the cutoff plane.
 * @param cap - the cap
 * @returns - the height
 */
export declare function height<T>(cap: S2Cap<T>): number;
/**
 * Constructs a cap with the given center and radius.  A negative radius
 * yields an empty cap; a radius of 180 degrees or more yields a full cap
 * (containing the entire sphere).  "center" should be unit length.
 * @param center - the center point
 * @param radius - the radius
 * @param data - the data
 * @returns - the cap
 */
export declare function fromS1Angle<T>(center: Point3D, radius: S1Angle, data: T): S2Cap<T>;
/**
 * Constructs a cap where the angle is expressed as an S1ChordAngle.  This
 * constructor is more efficient than the one above.
 * @param center - the center
 * @param radius - the radius
 * @param data - the data
 * @returns - the cap
 */
export declare function fromS1ChordAngle<T>(center: Point3D, radius: S1ChordAngle, data: T): S2Cap<T>;
/**
 * Convenience function that creates a cap containing a single point.  This
 * method is more efficient that the S2Cap(center, radius) constructor.
 * @param center - the center
 * @param data - the data
 * @returns - an empty cap
 */
export declare function fromS2Point<T>(center: Point3D, data: T): S2Cap<T>;
/**
 * Return the cap radius as an S1Angle.  (Note that the cap angle is stored
 * internally as an S1ChordAngle, so this method requires a trigonometric
 * operation and may yield a slightly different result than the value passed
 * to the (S2Point, S1Angle) constructor.)
 * @param cap - the cap
 * @returns - the radius as an S1Angle in radians
 */
export declare function radius<T>(cap: S2Cap<T>): S1Angle;
/**
 * Returns true if the cap contains the given point.
 * NOTE: The point "p" should be a unit-length vector.
 * @param cap - the cap
 * @param p - the point
 * @returns - true if the cap contains the point
 */
export declare function containsS2Point<T>(cap: S2Cap<T>, p: Point3D): boolean;
/**
 * Return the complement of the interior of the cap.  A cap and its
 * complement have the same boundary but do not share any interior points.
 * The complement operator is not a bijection because the complement of a
 * singleton cap (containing a single point) is the same as the complement
 * of an empty cap.
 * @param cap - the cap
 * @returns - the complement
 */
export declare function complement<T>(cap: S2Cap<T>): S2Cap<T>;
/**
 * Return true if the cap contains the given cell.
 * @param cap - the cap
 * @param cell - the cell
 * @returns - true if the cap contains the cell
 */
export declare function containsS2CellVertexCount<T>(cap: S2Cap<T>, cell: S2CellId): number;
/**
 * Return true if the cap contains the given cell.
 * @param cap - the cap
 * @param cell - the cell
 * @returns - true if the cap contains the cell
 */
export declare function containsS2Cell<T>(cap: S2Cap<T>, cell: S2CellId): boolean;
/**
 * Return true if the cap intersects "cell", given that the cap does intersect
 * any of the cell vertices or edges.
 * @param cap - the cap
 * @param cell - the cell
 * @returns - true if the cap intersects the cell
 */
export declare function intersectsS2CellFast<T>(cap: S2Cap<T>, cell: S2CellId): boolean;
/**
 * Return true if the cap intersects "cell", given that the cap does contain
 * any of the cell vertices (supplied in "vertices", an array of length 4).
 * Return true if this cap intersects any point of 'cell' excluding its
 * vertices (which are assumed to already have been checked).
 * @param cap - the cap
 * @param cell - the cell
 * @param vertices - the vertices of the cell
 * @returns - true if the cap intersects the cell
 */
export declare function intersectsS2Cell<T>(cap: S2Cap<T>, cell: S2CellId, vertices: Vertices): boolean;
/**
 * @param cap - the cap
 * @returns - the cells that intersect the cap
 */
export declare function getIntersectingCells<T>(cap: S2Cap<T>): S2CellId[];
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