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Style circles categorically

Additional Developer Resources
Add point data to a style from a vector tileset and use the match and get expressions to assign the color of each point in a CircleLayer based on a data property.

There are several ways to add markers, annotations, and other shapes to the map using the Maps SDK. To choose the appropriate approach for your application, read the Markers and annotations guide.

StyleCirclesCategoricallyActivity.kt
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package com.mapbox.maps.testapp.examples

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.mapbox.common.MapboxOptions
import com.mapbox.geojson.Point
import com.mapbox.maps.CameraOptions
import com.mapbox.maps.MapView
import com.mapbox.maps.MapboxMap
import com.mapbox.maps.Style
import com.mapbox.maps.extension.style.expressions.generated.Expression
import com.mapbox.maps.extension.style.expressions.generated.Expression.Companion.exponentialInterpolator
import com.mapbox.maps.extension.style.expressions.generated.Expression.Companion.literal
import com.mapbox.maps.extension.style.expressions.generated.Expression.Companion.match
import com.mapbox.maps.extension.style.expressions.generated.Expression.Companion.rgb
import com.mapbox.maps.extension.style.expressions.generated.Expression.Companion.zoom
import com.mapbox.maps.extension.style.layers.generated.circleLayer
import com.mapbox.maps.extension.style.sources.generated.vectorSource
import com.mapbox.maps.extension.style.style

/**
 * Add point data to a style from a vector tileset and use the match and
 * get expressions to assign the color of each point in a CircleLayer
 * based on a data property.
 */
class StyleCirclesCategoricallyActivity : AppCompatActivity() {

  private lateinit var mapboxMap: MapboxMap

  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val mapView = MapView(this)
    setContentView(mapView)
    mapboxMap = mapView.mapboxMap
    mapboxMap.loadStyle(
      style(Style.LIGHT) {

        +vectorSource("ethnicity-source") {
          url("http://api.mapbox.com/v4/examples.8fgz4egr.json?access_token=" + MapboxOptions.accessToken)
        }

        +circleLayer("population", "ethnicity-source") {
          sourceLayer("sf2010")
          circleRadius(
            exponentialInterpolator(
              base = 1.75,
              input = zoom(),
              stops = arrayOf(
                literal(12) to literal(2),
                literal(22) to literal(180)
              )
            )
          )
          circleColor(
            match(
              input = Expression.get("ethnicity"),
              stops = arrayOf(
                literal("white") to rgb(251.0, 176.0, 59.0),
                literal("Black") to rgb(34.0, 59.0, 83.0),
                literal("Hispanic") to rgb(229.0, 94.0, 94.0),
                literal("Asian") to rgb(59.0, 178.0, 208.0),
                literal("Other") to rgb(204.0, 204.0, 204.0),
              ),
              fallback = rgb(0.0, 0.0, 0.0)
            )
          )
        }
      }
    )

    mapboxMap.setCamera(
      CameraOptions.Builder()
        .center(Point.fromLngLat(-122.447303, 37.753574))
        .zoom(12.0)
        .build()
    )
  }
}
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