63 lines
2.3 KiB
JavaScript
Executable File
63 lines
2.3 KiB
JavaScript
Executable File
import centroid from '@turf/centroid';
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import rhumbBearing from '@turf/rhumb-bearing';
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import rhumbDistance from '@turf/rhumb-distance';
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import rhumbDestination from '@turf/rhumb-destination';
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import clone from '@turf/clone';
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import { coordEach } from '@turf/meta';
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import { getCoords } from '@turf/invariant';
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import { isObject } from '@turf/helpers';
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/**
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* Rotates any geojson Feature or Geometry of a specified angle, around its `centroid` or a given `pivot` point.
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*
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* @name transformRotate
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* @param {GeoJSON} geojson object to be rotated
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* @param {number} angle of rotation in decimal degrees, positive clockwise
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* @param {Object} [options={}] Optional parameters
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* @param {Coord} [options.pivot='centroid'] point around which the rotation will be performed
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* @param {boolean} [options.mutate=false] allows GeoJSON input to be mutated (significant performance increase if true)
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* @returns {GeoJSON} the rotated GeoJSON feature
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* @example
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* var poly = turf.polygon([[[0,29],[3.5,29],[2.5,32],[0,29]]]);
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* var options = {pivot: [0, 25]};
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* var rotatedPoly = turf.transformRotate(poly, 10, options);
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*
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* //addToMap
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* var addToMap = [poly, rotatedPoly];
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* rotatedPoly.properties = {stroke: '#F00', 'stroke-width': 4};
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*/
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function transformRotate(geojson, angle, options) {
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// Optional parameters
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options = options || {};
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if (!isObject(options)) throw new Error("options is invalid");
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var pivot = options.pivot;
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var mutate = options.mutate;
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// Input validation
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if (!geojson) throw new Error("geojson is required");
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if (angle === undefined || angle === null || isNaN(angle))
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throw new Error("angle is required");
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// Shortcut no-rotation
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if (angle === 0) return geojson;
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// Use centroid of GeoJSON if pivot is not provided
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if (!pivot) pivot = centroid(geojson);
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// Clone geojson to avoid side effects
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if (mutate === false || mutate === undefined) geojson = clone(geojson);
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// Rotate each coordinate
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coordEach(geojson, function (pointCoords) {
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var initialAngle = rhumbBearing(pivot, pointCoords);
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var finalAngle = initialAngle + angle;
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var distance = rhumbDistance(pivot, pointCoords);
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var newCoords = getCoords(rhumbDestination(pivot, distance, finalAngle));
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pointCoords[0] = newCoords[0];
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pointCoords[1] = newCoords[1];
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});
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return geojson;
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}
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export default transformRotate;
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