Scene - hitTest | Sample | ArcGIS Maps SDK for JavaScript

Use viewElement.hitTest() to get all graphics or features under the pointer at the moment of interaction. The method returns an ordered array (nearest first) of intersections from these sources: GraphicsLayer, FeatureLayer, SceneLayer, BuildingSceneLayer, PointCloudLayer, CSVLayer, StreamLayer, GeoJSONLayer, viewElement.graphics

What you get back (HitTestResult)

Each hit returns:

graphic – the matched graphic or feature (with attributes, if present)
mapPoint – the 3D point on the object
distance – camera-to-hit distance (in view units)

If the ground is intersected, ground.mapPoint and ground.distance are also provided.

To initiate the hitTest:

viewElement.addEventListener("arcgisViewImmediateClick", (event) => {
  viewElement.hitTest(event.detail)
  .then((hitTestResult) => {
    console.log(hitTestResult)
  })
  .catch((error) => {
    console.error(error);
  });
};

Example of a HitTestResult:

{
  "screenPoint": {
    "x": 1110.666748046875,
    "y": 704.6666870117188
  },
  "results": [
    {
      "graphic": {
        "geometry": null,
        "symbol": null,
        "attributes": {
          "OBJECTID": 23259,
          "CNSTRCT_YR": 1950
        }
      },
      "mapPoint": {
        "spatialReference": {
          "latestWkid": 3857,
          "wkid": 102100
        },
        "x": -8237578.175357298,
        "y": 4972677.452421391,
        "z": 29.343255893327296
      },
      "distance": 6033.217135564263
    }
  ],
  "ground": {
    "mapPoint": {
      "spatialReference": {
        "latestWkid": 3857,
        "wkid": 102100
      },
      "x": -8237575.894557083,
      "y": 4972679.5403643185,
      "z": 6.689946555570758
    },
    "distance": 6055.99127013477
  }
}

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
    <title>Scene - hitTest | Sample | ArcGIS Maps SDK for JavaScript</title>

    <!-- Load the ArcGIS Maps SDK for JavaScript from CDN -->
    <script type="module" src="https://js.arcgis.com/5.0/"></script>

    <style>
      html,
      body {
        margin: 0;
        height: 100%;
      }

      .panel-content {
        padding: 16px;
        display: flex;
        flex-direction: column;
      }
    </style>
  </head>

  <body>
    <arcgis-scene item-id="9a542f6755274436985617a462ffdf44">
      <arcgis-zoom slot="top-left"></arcgis-zoom>
      <arcgis-navigation-toggle slot="top-left"></arcgis-navigation-toggle>
      <arcgis-compass slot="top-left"></arcgis-compass>
      <calcite-panel slot="top-right">
        <div class="panel-content">
          <calcite-text> Click in the scene to get the hitTest results. </calcite-text>
          <br />
          <calcite-text>
            Distance to ground:
            <calcite-text id="hitResultGround">0 m</calcite-text>
          </calcite-text>
          <calcite-text>
            Objects hit:
            <calcite-text id="hitResultCount">-</calcite-text>
          </calcite-text>
          <br />
          <calcite-button id="reset">Reset</calcite-button>
        </div>
      </calcite-panel>
    </arcgis-scene>

    <script type="module">
      const [Graphic] = await $arcgis.import(["@arcgis/core/Graphic.js"]);
      /*****************************************************************
       * Get a reference to the HTML elements
       *****************************************************************/
      const viewElement = document.querySelector("arcgis-scene");

      // Wait for the view to initialize
      await viewElement.viewOnReady();

      viewElement.highlights = [{ name: "default", color: "cyan", haloOpacity: 0 }];

      // symbol for points on objects
      let objectPointSymbol = {
        type: "point-3d",
        symbolLayers: [
          {
            type: "icon", // autocasts as new IconSymbol3DLayer()
            size: 12, // points
            resource: { primitive: "circle" },
            material: { color: "dodgerblue" },
            outline: {
              color: "deepskyblue",
            },
          },
        ],
      };

      // symbol for first object hit point
      let firstObjectPointSymbol = {
        type: "point-3d",
        symbolLayers: [
          {
            type: "icon", // autocasts as new IconSymbol3DLayer()
            size: 12, // points
            resource: { primitive: "circle" },
            material: { color: "darkblue" },
            outline: {
              color: "deepskyblue",
            },
          },
        ],
      };

      // symbol for the ground point
      const groundPointSymbol = {
        type: "point-3d",
        symbolLayers: [
          {
            type: "icon", // autocasts as new IconSymbol3DLayer()
            size: 12, // points
            resource: { primitive: "circle" },
            material: { color: "darkgreen" },
            outline: {
              color: "limegreen",
            },
          },
        ],
      };
      // line symbol which connects the points
      const lineSymbol = {
        type: "line-3d", // autocasts as new LineSymbol3D()
        symbolLayers: [
          {
            type: "line", // autocasts as new LineSymbol3DLayer()
            material: {
              color: "dodgerblue",
            },
            size: 4,
          },
        ],
      };

      let highlightedList = [];
      const hitResultGround = document.getElementById("hitResultGround");
      const hitResultCount = document.getElementById("hitResultCount");
      const resetBtn = document.getElementById("reset");

      viewElement.addEventListener("arcgisViewImmediateClick", (event) => {
        // get the returned hitTestResult
        // and draw points on all return mappoints and connect to a line
        // (using promise chaining for cleaner code and error handling)
        viewElement
          .hitTest(event.detail, { exclude: [viewElement.graphics] })
          .then((hitTestResult) => {
            // print the information to the panel
            hitResultGround.textContent = `${Math.round(hitTestResult.ground.distance)} m`;
            hitResultCount.textContent = hitTestResult.results.length;

            let lastHit = null;
            if (hitTestResult.results.length > 0) {
              lastHit = hitTestResult.results[hitTestResult.results.length - 1];
              // create point graphic for each hit on objects
              hitTestResult.results.forEach((result, index) => {
                const hitObject = new Graphic({
                  geometry: result.mapPoint,
                  symbol: index === 0 ? firstObjectPointSymbol : objectPointSymbol,
                });
                viewElement.graphics.add(hitObject);

                let graphic = result.graphic;
                // change the layer to be transparent
                graphic.layer.opacity = 0.8;
                // highlight the hit object
                viewElement.whenLayerView(graphic.layer).then((layerView) => {
                  highlightedList.push(layerView.highlight(graphic));
                });
              });
            }

            if (hitTestResult.ground.mapPoint) {
              if (lastHit) {
                if (hitTestResult.ground.distance > lastHit.distance) {
                  // an object under the ground could be more far away,
                  // check first the distance before set the ground as last point
                  lastHit = hitTestResult.ground;
                }
              } else {
                lastHit = hitTestResult.ground;
              }
              // create point graphic for the ground
              const hitGround = new Graphic({
                geometry: hitTestResult.ground.mapPoint,
                symbol: groundPointSymbol,
              });
              viewElement.graphics.add(hitGround);
            }

            if (lastHit) {
              // Draw a line to connect all hit objects and ground
              let linePoints = [
                [
                  viewElement.camera.position.x,
                  viewElement.camera.position.y,
                  viewElement.camera.position.z,
                ],
                [lastHit.mapPoint.x, lastHit.mapPoint.y, lastHit.mapPoint.z],
              ];

              viewElement.graphics.add({
                geometry: {
                  type: "polyline",
                  paths: linePoints,
                  spatialReference: viewElement.spatialReference,
                },

                symbol: lineSymbol,
              });
            }
          })
          .catch((error) => {
            console.error(error);
          });
      });
      resetBtn.addEventListener("click", () => {
        // remove all graphics
        viewElement.graphics.removeAll();
        // remove the highlights
        highlightedList.forEach((highlightObject) => {
          highlightObject.remove();
        });
        highlightedList = [];
        // disable the transparency
        viewElement.map.layers.getItemAt(0).opacity = 1;
        // remove the result
        hitResultGround.textContent = "0 m";
        hitResultCount.textContent = "-";
      });
    </script>
  </body>
</html>