add: map re-renctering button, not tested

app/lib/widgets/choropleth_map.dart

@@ -28,6 +28,8 @@ class ChoroplethMap extends StatefulWidget {
 }
 
 class ChoroplethMapState extends State<ChoroplethMap> {
+  late final GlobalKey<ChoroplethMapState> _choroplethMapKey = GlobalKey();
+
   int selectedIndex = -1;            // Subdivision/map tile index
   late MapShapeSource dataSource;
   late final MapZoomPanBehavior _zoomPanBehavior = MapZoomPanBehavior();
@@ -36,6 +38,12 @@ class ChoroplethMapState extends State<ChoroplethMap> {
     _initDataSource();
   }
 
+  void resetZoom() {
+    setState(() {
+      _choroplethMapKey.currentState?.resetZoom();
+    });
+  }
+
   @override
   void initState() {
     super.initState();

app/lib/widgets/main_layout.dart

@@ -32,19 +32,20 @@ class MapContainerWidget extends StatefulWidget {
 }
 
 class _MapContainerWidgetState extends State<MapContainerWidget> {
+  // Button state trackers
   bool isMinimized = true;      // Quick view box state tacker
-
   bool satLayer = false;        // Satellite layer visibility state
   bool osmLayer = false;        // OSM layer visibility state
-
   bool isSatTapped = false;        // Satellite button tap state tracker
   bool isMapTapped = false;        // OSM button tap state tracker
+  bool infoLayer = false;   // Additional color information visibility
+  bool centerMap = false;   // Map centering button state tracker
 
-  bool infoLayer = false;  // Additional color legend visibility
-
+  // Initialise selected measurement to arbitrary value
   Measurement? selectedMeasurement = selectedMeasurements[0];
+  final GlobalKey<ChoroplethMapState> _choroplethMapKey = GlobalKey();
 
-  // Initialise lastUpdate variable from persistent storage if server fetch fails
+  /// Initialise lastUpdate variable from persistent storage if server fetch fails
   Future<void> checkAndSetLastUpdate() async {
     if (lastUpdate == null) {
       final prefs = await SharedPreferences.getInstance();
@@ -76,6 +77,13 @@ class _MapContainerWidgetState extends State<MapContainerWidget> {
     });
   }
 
+  /// Reset the map zoom and centering
+  void resetZoom() {
+    setState(() {
+      _choroplethMapKey.currentState?.resetZoom();
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     // Initialise selectedMarker to first element in markerList
@@ -109,6 +117,7 @@ class _MapContainerWidgetState extends State<MapContainerWidget> {
                     child: Padding(
                       padding: const EdgeInsets.all(15.0), // Padding around map
                       child: ChoroplethMap(
+                        key: _choroplethMapKey,
                         relation: widget.relation,
                         measurements: widget.measurements,
                         subdivisions: widget.subdivisions,
@@ -227,9 +236,42 @@ class _MapContainerWidgetState extends State<MapContainerWidget> {
                       ),
                     ),
                   ),
-                  Positioned( // Color info button
+                  Positioned( // Recenter map button
                     top: 130,
                     right: 10,
+                    child: GestureDetector(
+                      onTapDown: (_) {
+                        setState(() {
+                          centerMap = true;
+                        });
+                      },
+                      onTapUp: (_) {
+                        setState(() {
+                          centerMap = false;
+                        });
+                        resetZoom(); // Reset the map zoom
+                      },
+                      onTapCancel: () {
+                        setState(() {
+                          centerMap = false;
+                        });
+                      },
+                      child: Container(
+                        padding: const EdgeInsets.all(8),
+                        decoration: centerMap ? const BoxDecoration( // Add decoration only while pressed
+                          shape: BoxShape.circle,
+                          color: Colors.grey,
+                        ) : null,
+                        child: const Icon(
+                          Icons.center_focus_strong,
+                          color: Colors.white54,
+                        ),
+                      ),
+                    ),
+                  ),
+                  Positioned( // Color info button
+                    top: 170,
+                    right: 10,
                     child: GestureDetector(
                       onTap: () {
                         setState(() {