Examples
Dynamic styling (32)

Display water depth

package com.mapbox.mapboxandroiddemo.examples.dds;
import android.graphics.Color;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import com.mapbox.geojson.FeatureCollection;
import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.geometry.LatLng;
import com.mapbox.mapboxsdk.geometry.LatLngBounds;
import com.mapbox.mapboxsdk.maps.MapView;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
import com.mapbox.mapboxsdk.maps.Style;
import com.mapbox.mapboxsdk.style.layers.FillLayer;
import com.mapbox.mapboxsdk.style.layers.SymbolLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import java.io.InputStream;
import timber.log.Timber;
import static com.mapbox.mapboxsdk.style.expressions.Expression.eq;
import static com.mapbox.mapboxsdk.style.expressions.Expression.geometryType;
import static com.mapbox.mapboxsdk.style.expressions.Expression.get;
import static com.mapbox.mapboxsdk.style.expressions.Expression.interpolate;
import static com.mapbox.mapboxsdk.style.expressions.Expression.linear;
import static com.mapbox.mapboxsdk.style.expressions.Expression.literal;
import static com.mapbox.mapboxsdk.style.expressions.Expression.rgb;
import static com.mapbox.mapboxsdk.style.expressions.Expression.stop;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillColor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillOpacity;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textAllowOverlap;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textColor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textField;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.textSize;
public class BathymetryActivity extends AppCompatActivity implements OnMapReadyCallback {
private static final String GEOJSON_SOURCE_ID = "GEOJSON_SOURCE_ID";
private static final LatLngBounds LAKE_BOUNDS = new LatLngBounds.Builder()
.include(new LatLng(44.936236, -85.673450))
.include(new LatLng(44.932955, -85.669272))
.build();
private FeatureCollection featureCollection;
private MapView mapView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Mapbox access token is configured here. This needs to be called either in your application
// object or in the same activity which contains the mapview.
Mapbox.getInstance(this, getString(R.string.access_token));
// This contains the MapView in XML and needs to be called after the access token is configured.
setContentView(R.layout.activity_bathymetry);
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(this);
}
@Override
public void onMapReady(@NonNull final MapboxMap mapboxMap) {
mapboxMap.setStyle(Style.OUTDOORS, new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
// Set bounds to Lawrence Lake, Michigan
mapboxMap.setLatLngBoundsForCameraTarget(LAKE_BOUNDS);
// Remove lake label layer
style.removeLayer("water-label");
// Initialize FeatureCollection object for future use with layers
featureCollection = FeatureCollection.fromJson(loadGeoJsonFromAsset(
"bathymetry-data.geojson"));
// Retrieve GeoJSON from local file and add it to the map
style.addSource(new GeoJsonSource(GEOJSON_SOURCE_ID,
featureCollection));
setUpDepthFillLayers(style);
setUpDepthNumberSymbolLayer(style);
}
});
}
/**
* Adds a FillLayer and uses data-driven styling to display the lake's areas
*/
private void setUpDepthFillLayers(@NonNull Style loadedMapStyle) {
FillLayer depthPolygonFillLayer = new FillLayer("DEPTH_POLYGON_FILL_LAYER_ID", GEOJSON_SOURCE_ID);
depthPolygonFillLayer.withProperties(
fillColor(interpolate(linear(),
get("depth"),
stop(5, rgb(16, 158, 210)),
stop(10, rgb(37, 116, 145)),
stop(15, rgb(69, 102, 124)),
stop(30, rgb(31, 52, 67)))),
fillOpacity(.7f));
// Only display Polygon Features in this layer
depthPolygonFillLayer.setFilter(eq(geometryType(), literal("Polygon")));
loadedMapStyle.addLayer(depthPolygonFillLayer);
}
/**
* Adds a SymbolLayer to display the depth of the lake's areas
*/
private void setUpDepthNumberSymbolLayer(@NonNull Style loadedMapStyle) {
SymbolLayer depthNumberSymbolLayer = new SymbolLayer("DEPTH_NUMBER_SYMBOL_LAYER_ID",
GEOJSON_SOURCE_ID);
depthNumberSymbolLayer.withProperties(
textField("{depth}"),
textSize(17f),
textColor(Color.WHITE),
textAllowOverlap(true)
);
// Only display Point Features in this layer
depthNumberSymbolLayer.setFilter(eq(geometryType(), literal("Point")));
loadedMapStyle.addLayerAbove(depthNumberSymbolLayer, "DEPTH_POLYGON_FILL_LAYER_ID");
}
// Add the mapView lifecycle to the activity's lifecycle methods
@Override
public void onResume() {
super.onResume();
mapView.onResume();
}
@Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
@Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
@Override
public void onPause() {
super.onPause();
mapView.onPause();
}
@Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
@Override
protected void onDestroy() {
super.onDestroy();
mapView.onDestroy();
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
private String loadGeoJsonFromAsset(String filename) {
try {
// Load GeoJSON file
InputStream is = getAssets().open(filename);
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
return new String(buffer, "UTF-8");
} catch (Exception exception) {
Timber.e("Exception Loading GeoJSON: %s", exception.toString());
exception.printStackTrace();
return null;
}
}
}
Was this page helpful?