Illustrates the automatic reprojection of vectors to match the instance's CRS.

Information
?

Some informations embedded in the GeoJSON

    100% © Paris Data

    Display a map in EPGS:2154 with GeoJSON features displayed as meshes in various CRS, showing reprojection capabilities of FeatureCollection.

    index.js
    import { MathUtils } from "three/src/math/MathUtils.js";
    import GeoJSON from "ol/format/GeoJSON.js";
    import VectorSource from "ol/source/Vector.js";
    import { createXYZ } from "ol/tilegrid.js";
    import { tile } from "ol/loadingstrategy.js";
    
    import { Color, Vector3 } from "three";
    import { MapControls } from "three/examples/jsm/controls/MapControls.js";
    
    import Instance from "@giro3d/giro3d/core/Instance.js";
    import Extent from "@giro3d/giro3d/core/geographic/Extent.js";
    import Inspector from "@giro3d/giro3d/gui/Inspector.js";
    import FeatureCollection from "@giro3d/giro3d/entities/FeatureCollection.js";
    import Coordinates from "@giro3d/giro3d/core/geographic/Coordinates";
    
    Instance.registerCRS(
      "EPSG:2154",
      "+proj=lcc +lat_0=46.5 +lon_0=3 +lat_1=49 +lat_2=44 +x_0=700000 +y_0=6600000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs",
    );
    
    const extent = new Extent(
      "EPSG:2154",
      -111629.52,
      1275028.84,
      5976033.79,
      7230161.64,
    );
    
    const instance = new Instance({
      target: "view",
      crs: extent.crs,
    });
    
    // This is a GeoJSON with the default crs EPSG:4326
    const arrondissementSource = new VectorSource({
      format: new GeoJSON(),
      url: "./data/paris_arrondissements.geojson",
    });
    
    function getHue(area) {
      const minArea = 991153;
      const maxArea = 16372542;
      const hue = MathUtils.mapLinear(area, minArea, maxArea, 0.2, 0.8);
    
      return MathUtils.clamp(hue, 0, 1);
    }
    
    // Creates the entity. The features will automatically be reprojected before being displayed.
    const arrondissements = new FeatureCollection({
      source: arrondissementSource,
      extent,
      ignoreZ: true,
      minLevel: 0,
      maxLevel: 0,
      style: (feature) => {
        // The style depends on the polygon's area
        const t = getHue(feature.get("surface"));
        const highlight = feature.get("highlight");
        const brightness = highlight ? 1 : 0.7;
        const color = new Color().setHSL(0, t, brightness * t, "srgb");
    
        return {
          fill: {
            color,
            depthTest: false,
            renderOrder: 1,
          },
          stroke: highlight
            ? {
                color: "white",
                depthTest: false,
                renderOrder: 2,
              }
            : null,
        };
      },
    });
    arrondissements.name = "arrondissements";
    instance.add(arrondissements);
    
    // Another GeoJSON in EPSG:3857
    // Although this is non-standard in recent versions of
    // the GeoJSON specification, OpenLayers and Giro3D still
    // support GeoJSON files that have a different CRS than EPSG:4326.
    const perimeterqaaSource = new VectorSource({
      format: new GeoJSON(),
      url: "./data/perimetreqaa.geojson",
    });
    
    const perimeterqaa = new FeatureCollection({
      source: perimeterqaaSource,
      extent,
      ignoreZ: true,
      minLevel: 0,
      maxLevel: 0,
      style: (feature) => {
        const highlight = feature.get("highlight");
        return {
          fill: {
            color: highlight ? "#5d914d" : "#41822d",
            depthTest: false,
            opacity: 0.7,
            renderOrder: 3,
          },
          stroke: {
            color: "#85f516",
            lineWidth: highlight ? 4 : 1,
            depthTest: false,
            renderOrder: 4,
          },
        };
      },
    });
    perimeterqaa.name = "perimeterqaa";
    instance.add(perimeterqaa);
    
    // A WFS source in EPSG:3857
    const bdTopoSource = new VectorSource({
      format: new GeoJSON(),
      url: function url(bbox) {
        return `${
          "https://data.geopf.fr/wfs/ows" +
          "?SERVICE=WFS" +
          "&VERSION=2.0.0" +
          "&request=GetFeature" +
          "&typename=BDTOPO_V3:batiment" +
          "&outputFormat=application/json" +
          "&SRSNAME=EPSG:3857" +
          "&startIndex=0" +
          "&bbox="
        }${bbox.join(",")},EPSG:3857`;
      },
      strategy: tile(createXYZ({ tileSize: 512 })),
    });
    const buildings = new FeatureCollection({
      source: bdTopoSource,
      // we specify that FeatureCollection should reproject the features before displaying them
      dataProjection: "EPSG:3857",
      // We are working on a flat, 2D scene, so we must ignore the Z coordinate of features, if any.
      ignoreZ: true,
      extent,
      style: (feature) => {
        const properties = feature.getProperties();
        const highlighted = properties.highlight;
        let color = "#FFFFFF";
    
        if (highlighted) {
          color = "cyan";
        } else {
          if (properties.usage_1 === "Résidentiel") {
            color = "#9d9484";
          } else if (properties.usage_1 === "Commercial et services") {
            color = "#b0ffa7";
          }
        }
        return {
          fill: {
            color,
            depthTest: false,
            renderOrder: 5,
          },
          stroke: {
            color: "black",
            renderOrder: 6,
            depthTest: false,
          },
        };
      },
      minLevel: 11,
      maxLevel: 11,
    });
    buildings.name = "buildings";
    instance.add(buildings);
    
    const position = new Coordinates("EPSG:2154", 652212.5, 6860754.1, 27717.3);
    const lookAtCoords = new Coordinates("EPSG:2154", 652338.3, 6862087.1, 200);
    const lookAt = new Vector3(lookAtCoords.x, lookAtCoords.y, lookAtCoords.z);
    instance.view.camera.position.set(position.x, position.y, position.z);
    instance.view.camera.lookAt(lookAt);
    
    const controls = new MapControls(instance.view.camera, instance.domElement);
    controls.enableDamping = true;
    controls.dampingFactor = 0.2;
    controls.target.copy(lookAt);
    controls.saveState();
    instance.view.setControls(controls);
    
    // information on click
    const resultTable = document.getElementById("results");
    
    let previousObjects = [];
    const objectsToUpdate = [];
    
    function createResultTable(values) {
      resultTable.innerHTML = "";
    
      for (const value of values) {
        const child = document.createElement("li");
        // child.classList.add('list-group-item');
        child.innerText = value;
        resultTable.appendChild(child);
      }
    }
    
    function pick(e) {
      instance.notifyChange();
      // pick objects
      const pickedObjects = instance.pickObjectsAt(e, {
        radius: 2,
        where: [arrondissements, perimeterqaa],
      });
    
      // Reset highlights
      previousObjects.forEach((o) => o.userData.feature.set("highlight", false));
    
      const tableValues = [];
    
      if (pickedObjects.length !== 0) {
        resultTable.innerHTML = "";
    
        for (const p of pickedObjects) {
          const obj = p.object;
    
          const feature = obj.userData.feature;
          const entity = obj.userData.parentEntity;
    
          objectsToUpdate.push(obj);
    
          if (entity === arrondissements) {
            tableValues.push(feature.get("l_ar"));
          }
          if (entity === perimeterqaa) {
            tableValues.push("Improved Accessibility Zone");
          }
          // highlight it
          feature.set("highlight", true);
        }
      }
    
      createResultTable(tableValues);
    
      instance.notifyChange([...previousObjects, ...objectsToUpdate]);
      previousObjects = [...objectsToUpdate];
      objectsToUpdate.length = 0;
    }
    
    instance.domElement.addEventListener("mousemove", pick);
    
    Inspector.attach("inspector", instance);
    
    index.html
    <!doctype html>
    <html lang="en">
      <head>
        <title>Reprojection of features as mesh</title>
        <meta charset="UTF-8" />
        <meta name="name" content="feature_collection_reprojection" />
        <meta
          name="description"
          content="Illustrates the automatic reprojection of vectors to match the instance&#39;s CRS."
        />
        <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/latest/examples/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>
    
        <div class="side-pane-with-status-bar" style="min-height: 9rem">
          <div class="card">
            <h5 class="card-header">Information</h5>
    
            <!-- tooltip -->
            <span
              class="badge bg-secondary position-absolute top-0 end-0 m-2"
              data-bs-toggle="popover"
              data-bs-content="tooltip"
              >?</span
            >
    
            <p class="card-text d-none" id="tooltip">
              Some informations embedded in the GeoJSON
            </p>
    
            <div class="card-body pe-none">
              <!-- Result table -->
              <ul style="width: 12rem" id="results"></ul>
            </div>
          </div>
        </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": "feature_collection_reprojection",
        "dependencies": {
            "@giro3d/giro3d": "0.40.0"
        },
        "devDependencies": {
            "vite": "^3.2.3"
        },
        "scripts": {
            "start": "vite",
            "build": "vite build"
        }
    }