Display a TopoJSON file on a Map.

100% © OpenStreetMap contributors.
index.js
import TopoJSON from "ol/format/TopoJSON.js";
import OSM from "ol/source/OSM.js";
import { Fill, Stroke, Style } from "ol/style.js";

import { MapControls } from "three/examples/jsm/controls/MapControls.js";
import { CSS2DObject } from "three/examples/jsm/renderers/CSS2DRenderer.js";

import ColorLayer from "@giro3d/giro3d/core/layer/ColorLayer.js";
import Extent from "@giro3d/giro3d/core/geographic/Extent.js";
import Instance from "@giro3d/giro3d/core/Instance.js";
import Map from "@giro3d/giro3d/entities/Map.js";
import VectorSource from "@giro3d/giro3d/sources/VectorSource.js";
import Inspector from "@giro3d/giro3d/gui/Inspector.js";
import TiledImageSource from "@giro3d/giro3d/sources/TiledImageSource.js";
import Coordinates from "@giro3d/giro3d/core/geographic/Coordinates.js";

Instance.registerCRS(
  "EPSG:30174",
  "+proj=tmerc +lat_0=26 +lon_0=142 +k=0.9999 +x_0=0 +y_0=0 +ellps=bessel +towgs84=-146.414,507.337,680.507,0,0,0,0 +units=m +no_defs +type=crs",
);

const extent = new Extent(
  "EPSG:30174",
  -201012.900985493,
  -198191.63799031873,
  1066954.2964232096,
  1071890.8856167798,
);

const instance = new Instance({
  target: "view",
  crs: extent.crs,
});

const center = extent.centerAsVector2();

instance.view.camera.position.set(center.x, center.y - 1, 2000);

const controls = new MapControls(instance.view.camera, instance.domElement);
controls.enableDamping = true;
controls.dampingFactor = 0.25;
controls.target.set(center.x, center.y, 0);
instance.view.setControls(controls);

const map = new Map({ extent, backgroundColor: "#135D66" });
instance.add(map);

const buildingsStyle = (feature) => {
  const highlight = feature.get("highlight");
  const stroke = highlight
    ? new Stroke({
        color: "white",
        width: 2,
      })
    : undefined;

  return new Style({
    zIndex: highlight ? 1 : 0,
    fill: new Fill({
      color: highlight ? "green" : "red",
    }),
    stroke,
  });
};

const topoJsonSource = new VectorSource({
  data: {
    url: "https://3d.oslandia.com/giro3d/vectors/tokyo_buildings.topojson",
    format: new TopoJSON(),
  },
  dataProjection: "EPSG:4326",
  style: buildingsStyle,
});

const buildingsLayer = new ColorLayer({
  name: "Buildings",
  extent,
  source: topoJsonSource,
});

// Create the OpenStreetMap color layer using an OpenLayers source.
// See https://openlayers.org/en/latest/apidoc/module-ol_source_OSM-OSM.html
// for more informations.
const osm = new ColorLayer({
  name: "osm",
  source: new TiledImageSource({ source: new OSM() }),
  extent,
});

map.addLayer(osm);
map.addLayer(buildingsLayer);

const labelElement = document.createElement("span");
labelElement.classList.value = "badge rounded-pill text-bg-light";
labelElement.style.marginTop = "2rem";
const label = new CSS2DObject(labelElement);

label.visible = false;
instance.add(label);

let previousFeature;

function pickFeatures(mouseEvent) {
  const pickResult = instance.pickObjectsAt(mouseEvent, {
    radius: 0,
  });

  const picked = pickResult[0];

  function resetPickedFeatures() {
    if (previousFeature) {
      previousFeature.set("highlight", false);
      topoJsonSource.updateFeature(previousFeature);
    }
    if (label.visible) {
      label.visible = false;
    }
    previousFeature = null;
  }

  if (picked) {
    const { x, y } = picked.point;
    const features = buildingsLayer.getVectorFeaturesAtCoordinate(
      new Coordinates(instance.referenceCrs, x, y),
    );

    if (features.length > 0) {
      const firstFeature = features[0];

      previousFeature?.set("highlight", false);
      firstFeature.set("highlight", true);

      if (previousFeature !== firstFeature) {
        topoJsonSource.updateFeature(previousFeature, firstFeature);
        previousFeature = firstFeature;
      }

      instance.notifyChange(map);
      label.position.set(x, y, 100);
      label.visible = true;
      label.element.innerText = firstFeature.get("osm_id");
      label.updateMatrixWorld(true);
    } else {
      resetPickedFeatures();
    }
  } else {
    resetPickedFeatures();
  }
}

instance.domElement.addEventListener("mousemove", pickFeatures);
instance.domElement.addEventListener("dblclick", (e) =>
  console.log(instance.pickObjectsAt(e)),
);

Inspector.attach("inspector", instance);

instance.notifyChange(map);
index.html
<!doctype html>
<html lang="en">
  <head>
    <title>TopoJSON</title>
    <meta charset="UTF-8" />
    <meta name="name" content="ol_vector_topojson" />
    <meta name="description" content="Display a TopoJSON file on a Map." />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />

    <link rel="icon" href="https://giro3d.org/images/favicon.svg" />
    <link
      href="https://giro3d.org/assets/bootstrap-custom.css"
      rel="stylesheet"
    />
    <script src="https://giro3d.org/assets/bootstrap.bundle.min.js"></script>
    <link
      rel="stylesheet"
      type="text/css"
      href="https://giro3d.org/next/css/example.css"
    />
  </head>

  <body>
    <div id="view" class="m-0 p-0 w-100 h-100"></div>
    <div
      id="inspector"
      class="position-absolute top-0 start-0 mh-100 overflow-auto"
    ></div>

    <script type="module" src="index.js"></script>
    <script>
      /* activate popovers */
      const popoverTriggerList = [].slice.call(
        document.querySelectorAll('[data-bs-toggle="popover"]'),
      );
      popoverTriggerList.map(
        // bootstrap is used as script in the template, disable warning about undef
        // eslint-disable-next-line no-undef
        (popoverTriggerEl) =>
          new bootstrap.Popover(popoverTriggerEl, {
            trigger: "hover",
            placement: "left",
            content: document.getElementById(
              popoverTriggerEl.getAttribute("data-bs-content"),
            ).innerHTML,
            html: true,
          }),
      );
    </script>
  </body>
</html>
package.json
{
    "name": "ol_vector_topojson",
    "dependencies": {
        "@giro3d/giro3d": "git+https://gitlab.com/giro3d/giro3d.git"
    },
    "devDependencies": {
        "vite": "^3.2.3"
    },
    "scripts": {
        "start": "vite",
        "build": "vite build"
    }
}