Clusters as pie charts

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This sample demonstrates how to represent clusters as pie charts. This is done by calling the createRendererForClustering method in the pieChart smart mapping module.

This method returns a list of aggregate fields and a renderer. Both of these objects must be set on the FeatureReductionCluster object for the charts to properly render.

Configure clustering
Use dark colors for code blocks
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Add line.Add line.      async function generateClusterConfig(layer) {
        // generates default labelingInfo
        const { labelingInfo, clusterMinSize } = await clusterLabelCreator
          .getLabelSchemes({ layer, view: viewElement.view })
          .then((labelSchemes) => labelSchemes.primaryScheme);

        const labelSymbol = labelingInfo[0].symbol;
        labelSymbol.color = labelSymbol.haloColor.clone();
        labelSymbol.haloColor = [255, 255, 255, 0.3];
        labelSymbol.font.size = 10;


        const { renderer, fields } = await pieChartRendererCreator.createRendererForClustering({
          layer,
          shape: "donut",
        });

        renderer.holePercentage = 0.66;

        const fieldInfos = fields.map((field) => {
          return {
            fieldName: field.name,
            label: field.alias,
            format: {
              places: 0,
              digitSeparator: true,
            },
          };
        });

        // maps the field names for the popup chart
        const fieldNames = fieldInfos.map((field) => {
          return field.fieldName;
        });

        const popupTemplate = {
          content: [
            {
              type: "text",
              text: "This cluster represents <b>{cluster_count}</b> features.",
            },
            {
              type: "media",
              mediaInfos: [
                {
                  title: "311 Reports",
                  type: "pie-chart",
                  value: {
                    fields: fieldNames,
                  },
                },
              ],
            },
            {
              type: "fields",
            },
          ],
          fieldInfos,
        };

        return {
          type: "cluster",
          popupTemplate,
          labelingInfo,
          clusterMinSize,

          fields,
          renderer,

        };
      }

Clustering is enabled via the featureReduction property of the FeatureLayer.

Set generated cluster configuration
Use dark colors for code blocksCopy
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      await layer.when();
      const featureReduction = await generateClusterConfig(layer);
      layer.featureReduction = featureReduction;

Clustering is a method of aggregating features in a FeatureLayer, CSVLayer, GeoJSONLayer, WFSLayer, or OGCFeatureLayer by grouping them in clusters defined by screen space.