This sample demonstrates how point clustering can be used to group points into clusters based on their spatial proximity to one another. Clustering is enabled on the layer's featureReduction property.
Since feature is independent of the renderer, the symbol and popup of each cluster graphic can be used to summarize features within the cluster. See Clustering styles and configurations for more information about the various ways clusters can summarize the points they represent.
The layer's renderer in this sample visualizes weather data with three visual variables, each representing a different attribute:
- Color:
TEMP - Size:
WIND_SPEED - Rotation:
WIND_DIRECT
The renderer object looks like the the following:
const renderer = {
type: "simple", // autocasts as new SimpleRenderer()
symbol: {
type: "simple-marker", // autocasts as new SimpleMarkerSymbol()
// Arrow marker
path: "M14.5,29 23.5,0 14.5,9 5.5,0z",
color: [50, 50, 50],
outline: {
color: [0, 0, 0, 0.7],
width: 0.5
},
angle: 180,
size: 15
},
visualVariables: [
{
type: "rotation",
// Use {cluster_avg_WIND_DIRECT} in the
// featureReudction.popupTemplate to
// display the average temperature of all
// features within the cluster
field: "WIND_DIRECT",
rotationType: "geographic"
},
{
type: "size",
// Use {cluster_avg_WIND_SPEED} in the
// featureReudction.popupTemplate to
// display the average temperature of all
// features within the cluster
field: "WIND_SPEED",
minDataValue: 0,
maxDataValue: 60,
minSize: 8,
maxSize: 40
},
{
type: "color",
// Use {cluster_avg_TEMP} in the
// featureReudction.popupTemplate to
// display the average temperature of all
// features within the cluster
field: "TEMP",
stops: [
{ value: 20, color: "#2b83ba" },
{ value: 35, color: "#abdda4" },
{ value: 50, color: "#ffffbf" },
{ value: 65, color: "#fdae61" },
{ value: 80, color: "#d7191c" }
]
}
]
};
To enable clustering on the layer, you simply have to set the feature property to type cluster,
layer.featureReduction = {
type: "cluster"
};This will cluster the points using the default cluster (80px), and assign a symbol to each cluster conforming to the visual in the renderer in the following manner:
- Color: average
TEMPof all features in the cluster - Size: average
WIND_of all features in the clusterSPEED - Rotation: average
WIND_of all features in the clusterDIRECT
| No feature reduction | Clustered features |
|---|---|
|
) |
If a UniqueValueRenderer were used, the symbol of the predominant unique among the features in the cluster would be used to represent the cluster.
To provide more meaning to the app, you can configure a popupTemplate to display the average values of all the fields used by the renderer when the user clicks or taps the cluster.
const clusterConfig = {
type: "cluster",
popupTemplate: {
content: [{
type: "text",
text: "This cluster represents <b>{cluster_count}</b> weather stations."
}, {
type: "fields",
fieldInfos: [{
fieldName: "cluster_avg_WIND_SPEED",
label: "Average wind speed (km/h)",
format: {
places: 0
}
}, {
fieldName: "cluster_avg_WIND_DIRECT",
label: "Average wind direction (degrees)",
format: {
places: 0
}
}, {
fieldName: "cluster_avg_TEMP",
label: "Average temperature (°F)",
format: {
places: 0
}
}]
}]
}
};
Related samples and resources
Intro to clustering
Intro to clustering
Clustering - generate suggested configuration
Clustering - generate suggested configuration
Clustering - query clusters
Clustering - query clusters
Clustering - advanced configuration
Clustering - advanced configuration
Popup charts for point clusters
This sample demonstrates how to summarize clustered features using charts within a cluster's popup.
Clustering - filter popup features
This sample demonstrates how to filter clustered features within a cluster's popup.
FeatureReductionCluster
Read the API Reference for more information.