sg-heatmap/dist/es/extract.js

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

//
// Deprecated
// Switched to using GeoJSON
//

import fs from 'fs';
import xml2js from 'xml2js';
import { html2json as htmlParser } from 'html2json';
import { maxBy, minBy } from 'lodash';
import { encodePolyline, fromSVY21 } from './helpers/geometry';

var kmlParser = new xml2js.Parser({ explicitArray: false });

var kmls = {
  region: 'MP14_REGION_NO_SEA_PL.kml',
  planning_area: 'MP14_PLNG_AREA_NO_SEA_PL.kml',
  subzone: 'MP14_SUBZONE_NO_SEA_PL.kml'
};

Object.keys(kmls).forEach(function (layer) {
  var data = fs.readFileSync('data/raw/' + kmls[layer]);

  kmlParser.parseString(data, function (err, result) {
    if (err) console.error(err);
    var parsed = result.kml.Document.Folder.Placemark;
    fs.writeFileSync('data/semi/' + layer + '_raw.json', JSON.stringify(parsed));
    var cleaned = parsed.map(function (area) {
      var meta = area.description.replace(/\r?\n|\r/g, '');
      meta = htmlParser(meta).child[0].child.find(function (_ref) {
        var node = _ref.node,
            tag = _ref.tag;
        return node === 'element' && tag === 'body';
      }).child.find(function (_ref2) {
        var node = _ref2.node,
            tag = _ref2.tag;
        return node === 'element' && tag === 'table';
      }).child[1].child[0].child[0].child.reduce(function (tb, tr) {
        var key = tr.child[0].child[0].text.replace(/ /g, '_');
        var value = tr.child[1].child[0].text;
        tb[key] = value;
        return tb;
      }, {});
      var center = fromSVY21([meta.X_ADDR, meta.Y_ADDR]);
      var polygons = area.MultiGeometry.Polygon;
      var boundary = polygons instanceof Array ? polygons.map(formatPolygon) : [formatPolygon(polygons)];
      var key = meta.Subzone_Code || meta.Planning_Area_Code || meta.Region_Code;
      return { key: key, meta: meta, center: center, boundary: boundary };
    });
    fs.writeFileSync('data/' + layer + '.json', JSON.stringify(cleaned));
  });
});

function formatPolygon(polygon) {
  var outerBoundaryIs = polygon.outerBoundaryIs,
      innerBoundaryIs = polygon.innerBoundaryIs;

  var result = {};
  result.outer = formatLatLng(outerBoundaryIs.LinearRing.coordinates);
  result.bounds = {
    sw: [minBy(result.outer, function (v) {
      return v[0];
    })[0], minBy(result.outer, function (v) {
      return v[1];
    })[1]],
    ne: [maxBy(result.outer, function (v) {
      return v[0];
    })[0], maxBy(result.outer, function (v) {
      return v[1];
    })[1]]
  };
  result.outer = encodePolyline(result.outer);
  if (innerBoundaryIs) {
    result.inners = innerBoundaryIs instanceof Array ? innerBoundaryIs.map(function (b) {
      return formatLatLng(b.LinearRing.coordinates);
    }) : [formatLatLng(innerBoundaryIs.LinearRing.coordinates)];
    result.inners = result.inners.map(function (v) {
      return encodePolyline(v);
    });
  }
  return result;
}

function formatLatLng(str) {
  return str.trim().split(' ').map(function (substr) {
    var xyz = substr.split(',');
    return [+xyz[1], +xyz[0]];
  });
}