Work with layers

You can use the Maps SDK to add more styled data to the map at runtime. There are two key concepts to understand when preparing to add a layer to a style at runtime: layers and sources. Sources contain geographic data. They determine the shape of the features you’re adding to the map and where in the world they belong. Layers contain styling information. They determine how the data in a source should look on the map.

A layer is a styled representation of data of a single type (for example polygons, lines, or points) that make up a map style. For example, roads, city labels, and rivers would be three separate layers in a map. There are several layer types (for example fill, line, and symbol). You can read more about layers in the Mapbox Style Specification.

Most layers also require a source. The source provides map data that the Maps SDK can use with a style document to render a visual representation of that data. There are several source types (for example vector tilesets, GeoJSON, and raster data). You can read more about sources in the Mapbox Style Specification.

Style methods

In the Maps SDK, the Style class exposes the entry point for all methods related to the style object including sources and layers.

Style domain-specific language

The Style domain-specific language (DSL) is a collection of functions that allows composition of a style in a block that is applied to a receiver class. DSL functions are provided to construct Style, Layer, Source, Light, and Expression classes. The DSL function names match the class name being created, but the first character in the name is lowercase (for example, the DSL function for the CircleLayer class is circleLayer). In cases where there are mandatory constructor parameters of the class, assign the mandatory constructor parameters before the code block. Inside the DSL block, use code completion in Android Studio to find all available receiver functions.

With the Style DSL, authoring or updating map styles is like writing style JSON directly. The higher-level style API is exposed as DSL, allowing construction of a StyleExtension object using the same paradigm as creating Layer, Source, and Light classes using DSL and using the overloaded operator and inside the Style DSL closure to add layers, sources, or light to the StyleExtension.

Below is an example using the Style DSL to add a GeoJsonSource and a circle layer:

mapView.getMapboxMap().loadStyle(
  style(styleUri = Style.TRAFFIC_DAY) {
    +geoJsonSource(id = "earthquakes") {
      url(GEOJSON_URL)
      cluster(false)
    }
    +circleLayer(layerId = "earthquakeCircle", sourceId = "earthquakes") {
      circleRadius(get { literal("mag") })
      circleColor(Color.RED)
      circleOpacity(0.3)
      circleStrokeColor(Color.WHITE)
    }
  },
  object : Style.OnStyleLoaded {
    override fun onStyleLoaded(style: Style) {
      // Map is set up and the style has loaded. Now you can add data or make other map adjustments.
    }
  },
  object : OnMapLoadErrorListener {
    override fun onMapLoadError(mapViewLoadError: MapLoadError, msg: String) {
      // Error occurred when loading the map, try to handle it gracefully here
    }
  }
)

Sample code throughout this guide uses the Style DSL.

Add a layer at runtime

To add a new layer to the map at runtime, start by adding a source using the Style’s addSource method. It is important that you add the source for a new layer before attempting to add the layer itself because the source is a required parameter for most layer types.

Then, you’ll use the addLayer method to add the layer to the style. When adding the style layer, you will specify:

  • A unique ID that you assign to the new layer
  • The layer type (for example fill, line, or symbol)
  • What data to use by referencing a source
  • The appearance of the data by setting various properties (for example color, opacity, and language)

The sample code below illustrates how to add a GeoJSON source and then add and style a line layer that uses the data in that source.

// Get the style
mapView.getMapboxMap().getStyle { style ->
  // Specify a unique string as the source ID (SOURCE_ID)
  // and reference the location of source data
  +geoJsonSource(SOURCE_ID) {
    url("asset://from_crema_to_council_crest.geojson")
  }
  // Specify a unique string as the layer ID (LAYER_ID)
  // and reference the source ID (SOURCE_ID) added above.
  +lineLayer(LAYER_ID, SOURCE_ID) {
    lineColor(ContextCompat.getColor(this@DrawPolygonActivity, R.color.black))
    lineWidth(3.0)
  }
}

The exact available properties available when adding a source and layer varies by source type and layer type. Read more about source types and layer types below.

Update a layer at runtime

You can also udpate the style of any layer at runtime using the layer's unique layer ID with Style's getLayer or getLayerAs method and defining style properties.

The sample code below illustrates how to get an existing layer by referencing a layer ID and updaing the value of the fillOpacity's value.

// Get the style
mapView.getMapboxMap().getStyle { style ->
  // Get an existing layer by referencing its
  // unique layer ID (LAYER_ID)
  val layer = style.getLayerAs<FillLayer>(LAYER_ID)
  // Update layer properties
  layer.fillOpacity(0.7)
}

The exact available properties available when updating a layer varies by layer type. Read more about layer types below.

Specify order of a layers at runtime

Map styles contains many individual layers (for example, roads, buildings, labels, and more) that are stacked on top of each other. You can change the position of a layer at runtime using the moveStyleLayer API. The sample code below illustrates how to move an existing layer with the ID "population" below the layer with the ID "state-labels".

// Get the style
mapView.getMapboxMap().getStyle { style ->
  // Move position of the population layer
  // below the state-labels layer
  style.moveStyleLayer("population", LayerPosition(null, "state-labels", null))
}
Specify position of a layer when adding it to a style

By default, when you add a new layer to the style, it is placed on top of all the other layers. You can specify where the new layer is positioned relative to existing layers using layerAtPosition and specify if the layer should be positioned below or above another layer by referencing the layer ID (a string) or at a specific index (an integer).

// Get the style
mapView.getMapboxMap().getStyle { style ->
  +vectorSource("terrain-data") {
    url("mapbox://mapbox.mapbox-terrain-v2")
  }
  +layerAtPosition(
    lineLayer("terrain-data", "terrain-data") {
      sourceLayer("contour")
      lineWidth(1.9)
    },
    below = "road-label"
  )
}

Remove a layer at runtime

You can remove a layer from a style using Style's removeStyleLayer.

// Where LAYER_ID is a valid id of a layer that already
// exists in the style
mapView.getMapboxMap().getStyle { style ->
  // If a layer with a given layer ID exists in the
  // style, remove the layer
  if (style.styleLayerExists(LAYER_ID)) {
    style.removeStyleLayer(LAYER_ID)
  }
}

Source types

Vector

A vector source, VectorSource, is a vector tileset that conforms to the Mapbox Vector Tile format. A vector source contains geographic features (and their data properties) that have already been tiled. Learn more about the benefits of vector tilesets and how they work in the Vector tiles documentation. For vector tiles hosted by Mapbox, the "url" value should be of the form of mapbox://tilesetid.

style {
  // Specify a unique string as the source ID (SOURCE_ID)
  +vectorSource(SOURCE_ID) {
    url("mapbox://mapbox.mapbox-terrain-v2")
  }
}
Note

All style layers that use a vector source must specify a "source-layer" value.

GeoJSON

A GeoJSON source, GeoJsonSource, is data in the form of a JSON object that conforms to the GeoJSON specification. A GeoJSON source is a collection of one or more geographic features, which may be points, lines, and polygons. Data must be provided via a "data" property, whose value can be a URL or inline GeoJSON.

style {
  // Specify a unique string as the source ID (SOURCE_ID)
  +geoJsonSource(SOURCE_ID) {
    url("asset://from_crema_to_council_crest.geojson")
  }
}
Note

See the format of the data used in the sample code above in the Maps SDK example app on GitHub.

Raster

A raster source, RasterSource, is a raster tileset. For raster tiles hosted by Mapbox, the "url" value should be of the form mapbox://tilesetid.

style {
  // Specify a unique string as the source ID (SOURCE_ID)
  +rasterSource(SOURCE_ID) {
    tileSize(256)
    tileSet(TILESET_JSON, listOf(SOURCE_URL)) {}
  }
}

Raster DEM

A raster DEM source, RasterDemSource, refers to Mapbox Terrain-DEM (mapbox://mapbox.mapbox-terrain-dem-v1), which is the only supported raster DEM source.

style {
  // Specify a unique string as the source ID (SOURCE_ID)
  +rasterDemSource(SOURCE_ID) {
    url("mapbox://mapbox.mapbox-terrain-dem-v1")
    // 514 specifies padded DEM tile and provides better performance than 512 tiles.
    tileSize(514)
  }
}

Image

An image source, ImageSource, is an image that you supply along with geographic coordinates. Specify geographic coordinates in the "coordinates" array as [longitude, latitude] pairs so the SDK knows at what location in the world to place the image. Each coordinate pair in the "coordinates" array represents the image corners listed in clockwise order: top left, top right, bottom right, bottom left.

style {
  // Specify a unique string as the source ID (SOURCE_ID)
  +imageSource(SOURCE_ID) {
    coordinates(
      listOf(
        listOf(-80.11725, 25.7836),
        listOf(-80.1397431334, 25.783548),
        listOf(-80.13964, 25.7680),
        listOf(-80.11725, 25.76795)
      )
    )
  }
}

Layer types

Fill layer

A fill style layer, FillLayer, renders one or more filled (and optionally stroked) polygons on a map. You can use a fill layer to configure the visual appearance of polygon or multipolygon features.

To add a fill layer you need to first add a vector or GeoJSON source that contains polygon data. Then you can use the available properties in the FillLayer class to customize the appearance of the layer (for example, the color, opacity, or pattern).

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +fillLayer(LAYER_ID, SOURCE_ID) {
    fillColor(ContextCompat.getColor(context, R.color.black))
    fillOpacity(0.5)
  }
}
related
FillLayer

A filled polygon with an optional stroked border.

example
Tint a fill layer

Add an image to a style and use it to display a pattern in the landuse FillLayer in the Mapbox Streets style.

Line layer

A line style layer, LineLayer, renders one or more stroked polylines on the map. You can use a line layer to configure the visual appearance of polyline or multipolyline features.

To add a line layer, you need to first add a vector or GeoJSON source that contains line data. Then you can use the available properties in the LineLayer class to customize the appearance of the layer (for example, the color, width, or dasharray).

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +lineLayer(LAYER_ID, SOURCE_ID) {
    lineColor(ContextCompat.getColor(this@DrawPolygonActivity, R.color.black))
    lineWidth(3.0)
  }
}
related
LineLayer

A stroked line.

example
Draw a GeoJSON line

Load a polyline to a style using GeoJsonSource and display it on a map using LineLayer.

Symbol layer

A symbol style layer, SymbolLayer, renders icon and text labels at points or along lines on a map. You can use a symbol layer to configure the visual appearance of labels for features in vector tiles.

To add a symbol layer, you need to first add a vector or GeoJSON source that contains point data. If you want to use icons in this layer, you also need to add images to the style before adding the layer. Then you can use the available properties in the SymbolLayer class to customize the appearance of the layer.

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +symbolLayer(LAYER_ID, SOURCE_ID) {
    // set a few properties
  }
}
related
SymbolLayer

An icon or a text label.

example
Display multiple icon images in a symbol layer

Add point data and several images to a style and use the switchCase and get expressions to choose which image to display at each point in a SymbolLayer based on a data property.

Circle layer

A circle style layer, CirleLayer, renders one or more filled circles on a map. You can use a circle layer to configure the visual appearance of point or point collection features in vector tiles. A circle layer renders circles whose radii are measured in screen units.

To add a circle layer, you need to first add a vector or GeoJSON source that contains point data. Then you can use the available properties in the CircleLayer class to customize the appearance of the layer (for example, radius, color, or offset).

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +circleLayer(LAYER_ID, SOURCE_ID) {
    // set a few properties
  }
}
related
CircleLayer

A filled circle.

example
Style circles categorically

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.

Fill extrusion layer

A fill-extrusion, FillExtrusionLayer, style layer renders one or more filled (and optionally stroked) extruded (3D) polygons on a map. You can use a fill-extrusion layer to configure the extrusion and visual appearance of polygon or multipolygon features.

To add a fill extrusion layer, you need to first add a vector or GeoJSON source that contains polygon data. Often you will want the data to contain a data property that you will use to determine the height of extrusion of each feature. This may be a physical height in meters or a way to illustrate a non-physical attribute of the area like population in Census blocks. Once you've added an appropriate source, you can use the available properties in the FillExtrusionLayer class to customize the appearance of the layer (for example, the height, opacity, or color).

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +fillExtrusionLayer(LAYER_ID, SOURCE_ID) {
    fillExtrusionHeight(
      get("height")
    )
  }
}
Note

This example uses expressions to assign a value based on a data property. Read more about expressions in the Use expressions guide.

related
FillExtrusionLayer

An extruded (3D) polygon.

example
Display building extrusions

Extrude the building layer in the Mapbox Light style using FillExtrusionLayer and set up the light position.

Hillshade layer

A hillshade style layer, HillshadeLayer, renders digital elevation model (DEM) data on the client-side.

The implementation only supports Mapbox Terrain RGB and Mapzen Terrarium tiles. You must add either Mapbox Terrain RGB or Mapzen Terrarium as a source before adding a hillshade layer. Once you've added an appropriate source, you can use the available properties in the HillshadeLayer class to customize the appearance of the layer.

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +hillshadeLayer(LAYER_ID, SOURCE_ID) {
    // set a few properties
  }
}
related
HillshadeLayer

Client-side hillshading visualization based on DEM data. The implementation only supports Mapbox Terrain RGB and Mapzen Terrarium tiles.

Heatmap layer

A heatmap style layer, HeatmapLayer, renders a range of colors to represent the density of points in an area.

To add a heatmap layer, you need to first add a vector or GeoJSON source that contains point data. Then you can use the available properties in the HeatmapLayer class to customize the appearance of the layer.

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +heatmapLayer(LAYER_ID, SOURCE_ID) {
    // set a few properties
  }
}
related
HeatmapLayer

A heatmap.

example
Visualize data as a heatmap

Add earthquake frequency data to a style from a GeoJSON file and render it on a map using a HeatmapLayer.

Raster layer

A raster style layer, RasterLayer, renders raster tiles on a map. You can use a raster layer to configure the color parameters of raster tiles.

To add a raster layer, you need to first add a raster source. Then you can use the available properties in the RasterLayer class to customize the appearance of the layer.

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +rasterLayer(LAYER_ID, SOURCE_ID) {
    // set a few properties
  }
}
related
RasterLayer

Raster map textures such as satellite imagery.

example
Add animated weather data

Load a raster image to a style using ImageSource and display it on a map as animated weather data using RasterLayer.

Sky layer

A sky style layer, SkyLayer, renders a stylized spherical dome that encompasses the entire map and is automatically rendered behind all layers. This can be used to fill the area above the horizon with a simulated sky that illustrates a particular time-of-day, or stylized custom gradients.

You can use the available properties in the SkyLayer class to customize the appearance of the layer.

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +skyLayer(LAYER_ID, SOURCE_ID) {
    // set a few properties
  }
}
related
SkyLayer

A spherical dome around the map that is always rendered behind all other layers.

Background layer

The background style layer, BackgroundLayer, covers the entire map. Use a background style layer to configure a color or pattern to show below all other map content. If the background layer is transparent or omitted from the style, any part of the map view that does not show another style layer is transparent.

You can use the available properties in the BackgroundLayer class to customize the appearance of the layer.

style {
  // Specify a unique string as the layer ID (LAYER_ID)
  // and assign the source ID added above.
  +backgroundLayer(LAYER_ID, SOURCE_ID) {
    // set a few properties
  }
}
related
BackgroundLayer

The background color or pattern of the map.