sg-heatmap/dist/helpers/geometry.js

Open-source all-in-one Swiss Army knife tool for creating Choropleth maps

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();

exports.inside = inside;
exports.encodePolyline = encodePolyline;
exports.decodePolyline = decodePolyline;
exports.fromSVY21 = fromSVY21;
exports.toSVY21 = toSVY21;
exports.toLinearRing = toLinearRing;
exports.disjointBbox = disjointBbox;

var _polyline = require('@mapbox/polyline');

var _polyline2 = _interopRequireDefault(_polyline);

var _cloneDeep = require('lodash/cloneDeep');

var _cloneDeep2 = _interopRequireDefault(_cloneDeep);

var _svy = require('./svy21');

var _svy2 = _interopRequireDefault(_svy);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var PRECISION = 7;

var svy21 = new _svy2.default();

/* eslint-disable camelcase */
function inside(_ref, polyline) {
  var _ref2 = _slicedToArray(_ref, 2),
      lng = _ref2[0],
      lat = _ref2[1];

  var isInside = false;
  for (var i = 1; i < polyline.length; i++) {
    var deltaY_plus = polyline[i][1] - lat;
    var deltaY_minus = lat - polyline[i - 1][1];
    if (deltaY_plus > 0 && deltaY_minus <= 0) continue;
    if (deltaY_plus < 0 && deltaY_minus >= 0) continue;
    var deltaX = (deltaY_plus * polyline[i - 1][0] + deltaY_minus * polyline[i][0]) / (deltaY_plus + deltaY_minus) - lng;
    if (deltaX <= 0) continue;
    isInside = !isInside;
  }
  return isInside;
}
/* eslint-enable camelcase */

function encodePolyline(arr) {
  return _polyline2.default.encode(arr, PRECISION);
}

function decodePolyline(str) {
  return _polyline2.default.decode(str, PRECISION).map(function (_ref3) {
    var _ref4 = _slicedToArray(_ref3, 2),
        lng = _ref4[0],
        lat = _ref4[1];

    return [Math.round(lng * Math.pow(10, PRECISION - 2)) / Math.pow(10, PRECISION - 2), Math.round(lat * Math.pow(10, PRECISION - 2)) / Math.pow(10, PRECISION - 2)];
  });
}

function fromSVY21(_ref5) {
  var _ref6 = _slicedToArray(_ref5, 2),
      X = _ref6[0],
      Y = _ref6[1];

  var _svy21$computeLatLon = svy21.computeLatLon(Y, X),
      lat = _svy21$computeLatLon.lat,
      lon = _svy21$computeLatLon.lon;

  return [lon, lat];
}

function toSVY21(_ref7) {
  var _ref8 = _slicedToArray(_ref7, 2),
      lon = _ref8[0],
      lat = _ref8[1];

  var _svy21$computeSVY = svy21.computeSVY21(lat, lon),
      Y = _svy21$computeSVY.N,
      X = _svy21$computeSVY.E;

  return [X, Y];
}

function toLinearRing(polyline) {
  var linearRing = typeof polyline === 'string' ? decodePolyline(polyline) : (0, _cloneDeep2.default)(polyline);
  var firstPoint = linearRing[0];
  var lastPoint = linearRing[linearRing.length - 1];
  if (firstPoint[0] !== lastPoint[0] || firstPoint[1] !== lastPoint[1]) {
    linearRing.push(firstPoint);
  }
  return linearRing;
}

function disjointBbox(a, b) {
  if (a[0] < b[0] && a[2] < b[0]) return true;
  if (a[0] > b[2] && a[2] > b[2]) return true;
  if (a[1] < b[1] && a[3] < b[1]) return true;
  if (a[1] > b[3] && a[3] > b[3]) return true;
  return false;
}