Init commit

Generate a world/countries map, add simple pins, svg with circles

index.js

@@ -0,0 +1,117 @@
+const fs = require('fs');
+const proj4 = require('proj4');
+const inside = require('point-in-geopolygon');
+
+const geojsonWorld = JSON.parse(fs.readFileSync('./countries.geo.json', { encoding: 'utf8' }));
+const geojsonByCountry = geojsonWorld.features.reduce((countries, feature) => {
+  countries[feature.id] = feature;
+  return countries;
+}, {});
+
+const DEFAULT_WORLD_REGION = {
+  lat: { min: -65, max: 78 },
+  lng: { min: -179, max: 179 },
+};
+
+const computeGeojsonBox = (geojson) => {
+  const { type, features, geometry, coordinates } = geojson;
+  if (type === 'FeatureCollection') {
+    const boxes = features.map(computeGeojsonBox);
+    return {
+      lat: {
+        min: Math.min(...boxes.map((box) => box.lat.min)),
+        max: Math.max(...boxes.map((box) => box.lat.max)),
+      },
+      lng: {
+        min: Math.min(...boxes.map((box) => box.lng.min)),
+        max: Math.max(...boxes.map((box) => box.lng.max)),
+      },
+    };
+  } else if (type == 'Feature') {
+    return computeGeojsonBox(geometry);
+  } else if (type === 'MultiPolygon') {
+    return computeGeojsonBox({ type: 'Polygon', coordinates: coordinates.flat() });
+  } else if (type == 'Polygon') {
+    const coords = coordinates.flat();
+    const latitudes = coords.map(([_lng, lat]) => lat);
+    const longitudes = coords.map(([lng, _lat]) => lng);
+
+    return {
+      lat: {
+        min: Math.min(...latitudes),
+        max: Math.max(...latitudes),
+      },
+      lng: {
+        min: Math.min(...longitudes),
+        max: Math.max(...longitudes),
+      },
+    };
+  } else {
+    throw new Error(`Unknown geojson type ${type}`);
+  }
+};
+
+function DottedMap({ height = 0, width = 0, countries = [], region }) {
+  if (height <= 0 && width <= 0) {
+    throw new Error('height or width is required');
+  }
+
+  let geojson = geojsonWorld;
+  if (countries.length > 0) {
+    geojson = {
+      type: 'FeatureCollection',
+      features: countries.map((country) => geojsonByCountry[country]),
+    };
+    if (!region) {
+      region = computeGeojsonBox(geojson);
+    }
+  } else if (!region) {
+    region = DEFAULT_WORLD_REGION;
+  }
+
+  const [X_MIN, Y_MIN] = proj4(proj4.defs('GOOGLE'), [region.lng.min, region.lat.min]);
+  const [X_MAX, Y_MAX] = proj4(proj4.defs('GOOGLE'), [region.lng.max, region.lat.max]);
+  const X_RANGE = X_MAX - X_MIN;
+  const Y_RANGE = Y_MAX - Y_MIN;
+
+  if (width <= 0) {
+    width = Math.round((height * X_RANGE) / Y_RANGE);
+  } else if (height <= 0) {
+    height = Math.round((width * Y_RANGE) / X_RANGE);
+  }
+
+  const points = {};
+
+  for (let x = 0; x < width; x += 1) {
+    for (let y = 0; y < height; y += 1) {
+      const pointGoogle = [(x / width) * X_RANGE + X_MIN, Y_MAX - (y / height) * Y_RANGE];
+      const wgs84Point = proj4(proj4.defs('GOOGLE'), proj4.defs('WGS84'), pointGoogle);
+      if (inside.feature(geojson, wgs84Point) !== -1) {
+        points[[x, y].join(';')] = { x, y };
+      }
+    }
+  }
+
+  return {
+    addPin({ lat, lng, data, svgOptions }) {
+      const [rawX, rawY] = proj4(proj4.defs('GOOGLE'), [lng, lat]);
+      const [x, y] = [Math.round((width * (rawX - X_MIN)) / X_RANGE), Math.round((height * (Y_MAX - rawY)) / Y_RANGE)];
+      points[[x, y].join(';')] = { x, y, data, svgOptions };
+    },
+    getPoints() {
+      return Object.values(points);
+    },
+    getSVG({ shape, color = 'current', backgroundColor, radius = 0.5 }) {
+      return `<svg viewBox="0 0 ${width} ${height}" xmlns="http://www.w3.org/2000/svg">
+        ${Object.values(points)
+          .map(
+            ({ x, y, svgOptions = {} }) =>
+              `<circle cx="${x}" cy="${y}" r="${svgOptions.radius || radius}" fill="${svgOptions.color || color}" />`,
+          )
+          .join('\n')}
+      </svg>`;
+    },
+  };
+}
+
+module.exports = DottedMap;