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- import bearing from "@turf/bearing";
- import { bearingToAzimuth, isObject } from "@turf/helpers";
- import rhumbBearing from "@turf/rhumb-bearing";
- /**
- * Finds the angle formed by two adjacent segments defined by 3 points. The result will be the (positive clockwise)
- * angle with origin on the `startPoint-midPoint` segment, or its explementary angle if required.
- *
- * @name angle
- * @param {Coord} startPoint Start Point Coordinates
- * @param {Coord} midPoint Mid Point Coordinates
- * @param {Coord} endPoint End Point Coordinates
- * @param {Object} [options={}] Optional parameters
- * @param {boolean} [options.explementary=false] Returns the explementary angle instead (360 - angle)
- * @param {boolean} [options.mercator=false] if calculations should be performed over Mercator or WGS84 projection
- * @returns {number} Angle between the provided points, or its explementary.
- * @example
- * turf.angle([5, 5], [5, 6], [3, 4]);
- * //=45
- */
- function angle(startPoint, midPoint, endPoint, options) {
- if (options === void 0) { options = {}; }
- // Optional Parameters
- if (!isObject(options)) {
- throw new Error("options is invalid");
- }
- // Validation
- if (!startPoint) {
- throw new Error("startPoint is required");
- }
- if (!midPoint) {
- throw new Error("midPoint is required");
- }
- if (!endPoint) {
- throw new Error("endPoint is required");
- }
- // Rename to shorter variables
- var A = startPoint;
- var O = midPoint;
- var B = endPoint;
- // Main
- var azimuthAO = bearingToAzimuth(options.mercator !== true ? bearing(A, O) : rhumbBearing(A, O));
- var azimuthBO = bearingToAzimuth(options.mercator !== true ? bearing(B, O) : rhumbBearing(B, O));
- var angleAO = Math.abs(azimuthAO - azimuthBO);
- // Explementary angle
- if (options.explementary === true) {
- return 360 - angleAO;
- }
- return angleAO;
- }
- export default angle;
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