update: still no map, but progress

app/lib/pages/default_page.dart

@@ -17,14 +17,17 @@ class _DefaultPageState extends State<DefaultPage> {
   bool showBar = false;
 
   List<Measurement> markerList = [];
+  String relation = '';
 
   // Call fetchMarkerTemplate and await its result before setting the state
   Future<void> loadMarkerList() async {
     try {
       List<Measurement> fetchedMarkers = await fetchMarkerData();
+      String fetchedRelation = await fetchRelation();
 
       setState(() {
         markerList = fetchedMarkers;
+        relation = fetchedRelation;
       });
     } catch (e) {
       showDialog(
@@ -95,7 +98,7 @@ class _DefaultPageState extends State<DefaultPage> {
           ),
           body: ListView(
             children: [ // Add main widget
-              MapContainerWidget(markerList: markerList),
+              MapContainerWidget(markerList: markerList, relation: relation),
             ],
           ),
         ),

app/lib/pages/marker_handler/get_markers.dart

@@ -42,3 +42,34 @@ Future<List<Measurement>> fetchMarkerData() async {
   }
 }
 
+// fetchRelation requests lake relation data from the server
+Future<String> fetchRelation() async {
+  try {
+    // Custom HTTP client
+    HttpClient client = HttpClient()
+      ..badCertificateCallback = // NB: temporary disable SSL certificate validation
+          (X509Certificate cert, String host, int port) => true;
+
+    // Request markers from server
+    var request = await client.getUrl(Uri.parse(serverURI + 'get_relation'));
+    var response = await request.close(); // Close response body at end of function
+
+    // Parse body to JSON if request is ok
+    if (response.statusCode == 200) {
+      var responseBody = await response.transform(utf8.decoder).join();
+
+      if (responseBody.isNotEmpty) {
+        return responseBody;
+        } else {
+        throw Exception('Failed to fetch relation, body is empty');
+      }
+    } else {
+      throw Exception('Failed to fetch relation: Status code ${response.statusCode}');
+    }
+  } catch (e) {
+    throw Exception('Failed to fetch relation: ${e.toString()}');
+  }
+}
+
+
+

app/lib/pages/widgets/cloropleth_map.dart

 import 'dart:convert';
 import 'package:flutter/material.dart';
-import 'package:http/http.dart' as http;
 import 'package:syncfusion_flutter_maps/maps.dart';
 
-
 class ChoroplethMap extends StatefulWidget {
+  final String relation;
+
+  const ChoroplethMap({Key? key,
+    required this.relation,
+  }) : super(key: key);
+
   @override
   _ChoroplethMapState createState() => _ChoroplethMapState();
 }
 
-class _ChoroplethMapState extends State {
+class _ChoroplethMapState extends State<ChoroplethMap> {
   late MapShapeSource mapShapeSource;
 
   @override
   void initState() {
     super.initState();
-    getRelation().then((geojsonData) {
-      setState(() {
-        final geoJsonData = json.decode(geojsonData);
-
-        mapShapeSource = MapShapeSource.asset(
-          geoJsonData,
-          shapeDataField: 'coordinates',
-          dataCount: geoJsonData.length,
-          primaryValueMapper: (int index) {
-            return 'lake'; // NB: temp hardcoded value, no subdivisions yet
-          },
-        );
-      });
-    }).catchError((error) {
-      throw Exception('Failed to retrieve geojson data');
+    final geoJsonData = json.decode(widget.relation); // Decode the JSON string
+    final coordinates = geoJsonData['features'][0]['geometry']['coordinates'][0];
+
+    setState(() {
+      mapShapeSource = MapShapeSource.asset(
+        widget.relation,
+        shapeDataField: 'coordinates',
+        dataCount: coordinates.length,
+        primaryValueMapper: (int index) {
+          return 'lake'; // NB: temp hardcoded value, no subdivisions yet
+        },
+      );
     });
+
   }
 
   @override
@@ -40,23 +42,9 @@ class _ChoroplethMapState extends State {
         MapShapeLayer(
           source: mapShapeSource,
           strokeColor: Colors.white30,
-          legend: const MapLegend.bar(
-            MapElement.shape,
-            position: MapLegendPosition.bottom,
-            segmentSize: Size(55.0, 9.0),
-          ),
         ),
       ],
     );
   }
-
-  // getRelation requests the polygon coordinates from the server
-  Future<String> getRelation() async {
-    final response = await http.get(Uri.parse('get_relation'));
-    if (response.statusCode == 200) {
-      return response.body;
-    } else {
-      throw Exception('Failed to retrieve geojson data from server. Status code: ${response.statusCode}');
-    }
-  }
 }
+

app/lib/pages/widgets/map_widget.dart

@@ -14,8 +14,12 @@ import 'package:latlong2/latlong.dart' as latLng;
 /// its layers, polygons and markers.
 class MapContainerWidget extends StatefulWidget {
   final List<Measurement> markerList;
+  final String relation;
 
-  const MapContainerWidget({Key? key, required this.markerList}) : super(key: key);
+  const MapContainerWidget({Key? key,
+    required this.markerList,
+    required this.relation,
+  }) : super(key: key);
 
   @override
   _MapContainerWidgetState createState() => _MapContainerWidgetState();
@@ -60,7 +64,7 @@ class _MapContainerWidgetState extends State<MapContainerWidget> {
                   SizedBox(
                     width: screenWidth * boxWidth,
                     height: screenWidth * boxHeight,
-                    child: ChoroplethMap()
+                    child: ChoroplethMap(relation: widget.relation)
                     /*FlutterMap(
                       options: MapOptions(
                         center: mapCenter,