title: Limit Marker within city limit flutter map
body: <p>I have an requirement, in which Marker should be placed on clicking the Map within the city limit in flutter map and mapbox API. If user clicks on the map outside the city limit. Need to show an warning. I know it is possible to add marker on clicking on the map but how can I restrict it to city limit? I tried exploring the concept of GeoJson to add an layer above my Map. But I am not sure how this would help. Any suggestion appreciated.</p>
  <p>Thanks</p>
  <pre>
   FlutterMap(
                                            options: MapOptions(
                                              
                                                center: LatLng(
                                                    lat.latitude, lat.longitude),
                                                zoom: 12.0,
                                                maxZoom: 20.0,
                                                minZoom: 5.0,
                                                onTap: (value) {
                                                  setState(() {
                                                    latLng = value;
                                                    print(latLng);
                                                  });
                                                }),
                                            layers: [
                                              new TileLayerOptions(
                                                maxZoom: 20.0,
                                                urlTemplate:
                                                    'https://api.mapbox.com/tiles/{z}/{x}/{y}@2x?access_token=$kApiKey',
                                                additionalOptions: {
                                                  'accessToken': '$kApiKey',
                                    
                                                },
                                              ),
                                          
                                            
                                            ],
                                            mapController: mapController,
                                          ),
  </pre>
  <p><a href="https://i.stack.imgur.com/JS1BZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JS1BZ.png" alt="enter image description here" /></a></p>