update: add color value mapping

app/lib/widgets/choropleth_map.dart

@@ -66,7 +66,29 @@ class _ChoroplethMapState extends State<ChoroplethMap> {
                 shapeDataField: 'sub_div_id',
                 dataCount: count,
                 primaryValueMapper: (int index) => subdivisions[index].sub_div_id,
-                shapeColorValueMapper: (int index) => subdivisions[index].color,
+                shapeColorValueMapper: (int index) => subdivisions[index].avgThickness,
+                shapeColorMappers: const [
+                  MapColorMapper(
+                      from: 0,
+                      to: 4,
+                      color: Color(0xFFff0000),
+                      text: '{0},{25}'),
+                  MapColorMapper(
+                      from: 4,
+                      to: 7,
+                      color: Color(0xffff6a00),
+                      text: '75'),
+                  MapColorMapper(
+                      from: 7,
+                      to: 10,
+                      color:  Color(0xFFb1ff00),
+                      text: '150'),
+                  MapColorMapper(
+                      from: 10,
+                      to: 400,
+                      color:  Color(0xff4fa8d7),
+                      text: '400'),
+                ],
               ),
               zoomPanBehavior: _zoomPanBehavior,
               strokeColor: Colors.blue.shade50,
@@ -75,12 +97,13 @@ class _ChoroplethMapState extends State<ChoroplethMap> {
               onSelectionChanged: (int index) {
                 setState(() {
                   selectedIndex = index;
-                  for (int i = 0; i < subdivisions.length; i++) {
-                    subdivisions[i].color = i == index ? Colors.red : subdivisions[i].savedColor;
-                  }
                 });
                 widget.onSelectionChanged(selectedIndex);
               },
+              selectionSettings: const MapSelectionSettings(
+                strokeWidth: 3.0, // Increase stroke width
+                color: Colors.black,
+              ),
             ),
           ],
         ),