"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
exports.offsetPolygon = offsetPolygon;
const proj4_1 = __importDefault(require("proj4"));
const turf = __importStar(require("@turf/turf"));
// Function to offset a polygon by a given distance
/**
* Offsets a polygon by a given distance and reprojects the coordinates.
*
* @param polygonCoords - The coordinates of the polygon to be offset. It is a 3D array of numbers.
* @param offsetDistance - The distance by which to offset the polygon.
* @param spatialReference - The spatial reference system identifier (e.g., EPSG code) for the input coordinates.
* @returns The new polygon with offset coordinates in the original projection.
* @throws Will throw an error if the offset polygon is undefined.
*/
function offsetPolygon(polygonCoords, offsetDistance, spatialReference) {
const WGS84 = proj4_1.default.WGS84;
const sourceProjection = `EPSG:${spatialReference}`;
const reprojectedCoords = polygonCoords[0].map((coord) => {
return (0, proj4_1.default)(sourceProjection, WGS84, coord);
});
//console.log(reprojectedCoords)
// Create a GeoJSON Polygon feature from the coordinates
const polygon = turf.polygon([reprojectedCoords]);
//console.log(polygon.geometry.coordinates)
// Offset (buffer) the polygon by the given distance
const offsetPolygon = turf.buffer(polygon, offsetDistance, { units: 'feet', steps: 5 });
// Reproject the offset polygon back to the original projection
if (!offsetPolygon) {
throw new Error('Offset polygon is undefined');
}
const offsetCoords = offsetPolygon.geometry.coordinates[0].map((coord) => {
return (0, proj4_1.default)(WGS84, sourceProjection, coord);
});
// Return the new polygon in the original projection
return turf.polygon([offsetCoords]);
}