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Circle Layer (with Clustering)
{{ activity_source_note("CircleLayerActivity.kt") }}
In this example we will add a circle layer for a GeoJSON source. We also show how you can use the cluster property of a GeoJSON source.
Create a GeoJsonSource instance, pass a unique identifier for the source and the URL where the GeoJSON is available. Next add the source to the style.
--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/CircleLayerActivity.kt:addBusStopSource"
Now you can create a CircleLayer, pass it a unique identifier for the layer and the source identifier of the GeoJSON source just created. You can use a PropertyFactory to pass circle layer properties. Lastly add the layer to your style.
--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/CircleLayerActivity.kt:addBusStopCircleLayer"
Clustering
Next we will show you how you can use clustering. Create a GeoJsonSource as before, but with some additional options to enable clustering.
--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/CircleLayerActivity.kt:addClusteredSource"
When enabling clustering some special attributes will be available to the points in the newly created layer. One is cluster, which is true if the point indicates a cluster. We want to show a bus stop for points that are not clustered.
--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/CircleLayerActivity.kt:unclusteredLayer"
Next we define which point amounts correspond to which colors. More than 150 points will get a red circle, clusters with 21-150 points will be green and clusters with 20 or less points will be green.
--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/CircleLayerActivity.kt:clusteredCircleLayers"
Lastly we iterate over the array of Pairs to create a CircleLayer for each element.
--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/CircleLayerActivity.kt:clusteredCircleLayersLoop"