# Extrude polygons for 3D indoor mapping

> **Note (legacy): A newer version of the Maps SDK is available**
> 
> This page uses v9.7.1 of the Mapbox Maps SDK. A newer version of the SDK is available. Learn about the latest version, v11.29.0, in the [Maps SDK documentation](https://docs.mapbox.com/android/maps/guides/).

![Create a 3D indoor map with the fill-extrude-height paint property.](https://docs.mapbox.com/android/assets/ideal-img/maps-examples-extrude-polygons-for-3d-indoor-mapping.0187fa1.480.png)

> **Note**
> 
> This example is a part of the [Mapbox Android Demo app](https://github.com/mapbox/mapbox-android-demo). You can find the values for all referenced resources in the [`res`](https://github.com/mapbox/mapbox-android-demo/tree/master/MapboxAndroidDemo/src/main/res) directory. For example, see [`res/values/activity_strings.xml`](https://github.com/mapbox/mapbox-android-demo/tree/master/MapboxAndroidDemo/src/main/res/values/activity_strings.xml) for `R.string.*` references used in this example. The dependencies can be found [here.](https://github.com/mapbox/mapbox-navigation-android-examples/blob/main/app/build.gradle) The examples use View binding. [See setup documention if necessary.](https://developer.android.com/topic/libraries/view-binding)

Title: `activity_indoor_3d_map`

[View on GitHub](https://github.com/mapbox/mapbox-android-demo/tree/master/MapboxAndroidDemo/src/main/res/layout/activity_indoor_3d_map.xml)

```xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              xmlns:mapbox="http://schemas.android.com/apk/res-auto"
              android:layout_height="match_parent">

    <com.mapbox.mapboxsdk.maps.MapView
        android:id="@+id/mapView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        mapbox:mapbox_cameraTargetLat="41.86625"
        mapbox:mapbox_cameraTargetLng="-87.61694"
        mapbox:mapbox_cameraZoom="15.99"
        mapbox:mapbox_cameraBearing="20"
        mapbox:mapbox_cameraTilt="40"
        />


</LinearLayout>
```

**Java**

Title: `Indoor3DMapActivity.java`

[View on GitHub](https://github.com/mapbox/mapbox-android-demo/tree/master/MapboxAndroidDemo/src/main/java/com/mapbox/mapboxandroiddemo/examples/extrusions/Indoor3DMapActivity.java)

```java
package com.mapbox.mapboxandroiddemo.examples.extrusions;

import android.os.Bundle;

import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
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.FillExtrusionLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;

import java.net.URI;
import java.net.URISyntaxException;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import timber.log.Timber;

import static com.mapbox.mapboxsdk.style.expressions.Expression.get;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillExtrusionBase;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillExtrusionColor;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillExtrusionHeight;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.fillExtrusionOpacity;

/**
 * Create a 3D indoor map with the fill-extrude-height paint property
 */
public class Indoor3DMapActivity extends AppCompatActivity {

  private MapView mapView;

  @Override
  protected void onCreate(@Nullable 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_indoor_3d_map);

    mapView = findViewById(R.id.mapView);
    mapView.onCreate(savedInstanceState);
    mapView.getMapAsync(new OnMapReadyCallback() {
      @Override
      public void onMapReady(@NonNull final MapboxMap mapboxMap) {
        mapboxMap.setStyle(Style.MAPBOX_STREETS, new Style.OnStyleLoaded() {
          @Override
          public void onStyleLoaded(@NonNull Style style) {
            try {
              style.addSource(new GeoJsonSource("room-data", new URI("asset://indoor-3d-map.geojson")));

              style.addLayer(new FillExtrusionLayer(
                "room-extrusion", "room-data").withProperties(
                fillExtrusionColor(get("color")),
                fillExtrusionHeight(get("height")),
                fillExtrusionBase(get("base_height")),
                fillExtrusionOpacity(0.5f)
              ));
            } catch (URISyntaxException exception) {
              Timber.d(exception);
            }
          }
        });
      }
    });
  }

  @Override
  protected void onResume() {
    super.onResume();
    mapView.onResume();
  }

  @Override
  protected void onStart() {
    super.onStart();
    mapView.onStart();
  }

  @Override
  protected void onStop() {
    super.onStop();
    mapView.onStop();
  }

  @Override
  protected void onPause() {
    super.onPause();
    mapView.onPause();
  }

  @Override
  protected void onDestroy() {
    super.onDestroy();
    mapView.onDestroy();
  }

  @Override
  public void onLowMemory() {
    super.onLowMemory();
    mapView.onLowMemory();
  }

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    mapView.onSaveInstanceState(outState);
  }
}
```