update: calculate lat and lng based on distance in km

app/lib/consts.dart

@@ -12,7 +12,8 @@ const String mapEndpoint = "update_map";
 // Map variables
 String selectedLake = 'Mjøsa'; // NB should be initialised to last selected lake
 Uint8List selectedRelation = Uint8List(0);
-List<Measurement> selectedMarkerList = [];
+List<Measurement> selectedMeasurements = [];
+List<SubDiv> selectedSubdivisions = [];
 SubDiv? selectedSubDiv;
 
 LatLng mapCenter = LatLng(60.8000, 10.8471); // NB may not be necessary

app/lib/pages/default_page.dart

@@ -86,7 +86,7 @@ class _DefaultPageState extends State<DefaultPage> {
             child: ListView(
               children: [
                 MapContainerWidget(
-                  measurements: selectedMarkerList,
+                  measurements: selectedMeasurements,
                   relation: selectedRelation,
                   serverConnection: serverConnection,
                 ),

app/lib/server_requests/init_state.dart

@@ -6,7 +6,7 @@ import 'package:app/consts.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 import '../data_classes.dart';
-import '../server_requests/fetch_markers.dart';
+import '../server_requests/fetch_measurements.dart';
 import '../server_requests/fetch_relation.dart';
 
 /// initialiseState makes three requests to the server, one requesting
@@ -14,6 +14,7 @@ import '../server_requests/fetch_relation.dart';
 /// and the last requesting the list of all system lakes
 Future<void> initialiseState(bool fetchSearchOptions) async {
   bool serverConnection = true;
+  bool internetConnection = false;
 
   late Future<List<Measurement>> markerListFuture;
   late Future<Uint8List> relationFuture;
@@ -24,7 +25,9 @@ Future<void> initialiseState(bool fetchSearchOptions) async {
 
       FetchResult fetchResult = await loadMeasurements();
       List<Measurement> measurements = fetchResult.measurements;
-      selectedMarkerList = measurements;
+      selectedMeasurements = measurements;
+
+      print("Loaded from files: Meas.len: ${selectedMeasurements.length}, rel.len: ${selectedRelation.length}");
 
     } else { // Try to fetch measurement data from server
       markerListFuture = fetchMeasurements().then((fetchResult) {
@@ -52,7 +55,7 @@ Future<void> initialiseState(bool fetchSearchOptions) async {
 
       //selectedRelation = await relationFuture;
       selectedRelation = await relationFuture; // NB update once fixed
-      selectedMarkerList = await markerListFuture;
+      selectedMeasurements = await markerListFuture;
     }
   } catch (e) {
     // Handle any errors that occur during the initialization process

app/lib/utils/export_data.dart

@@ -12,7 +12,7 @@ Future<void> _exportIceData() async {
   final file = File('${directory?.path}/ice_data_$selectedLake.json');
 
   // Convert JSON data to string
-  final jsonString = jsonEncode(selectedMarkerList);
+  final jsonString = jsonEncode(selectedMeasurements);
 
   // Write JSON data to file
   await file.writeAsString(jsonString);

app/lib/widgets/main_layout.dart

@@ -37,7 +37,7 @@ class _MapContainerWidgetState extends State<MapContainerWidget> {
   bool isSatTapped = false;        // Satellite button tap state tracker
   bool isMapTapped = false;        // OSM button tap state tracker
 
-  Measurement? selectedMeasurement = selectedMarkerList[0];
+  Measurement? selectedMeasurement = selectedMeasurements[0];
 
   // Initialise lastUpdate variable from persistent storage if server fetch fails
   Future<void> checkAndSetLastUpdate() async {

server/map_handler/add_new_lake.py

 import os
 import json
+from math import cos, sqrt, fabs
 import random
 import geopandas as gpd
 from matplotlib import pyplot as plt
@@ -8,6 +9,20 @@ from shapely.geometry import Polygon, LineString, MultiLineString
 
 from server.consts import LAKE_RELATIONS_PATH
 
+'''
+# 0
+starting coordinate (x,y)
+
+# 1
+1 deg lat = 111.32km
+1 deg lng = 40075km * cos( lat ) / 360
+
+# 2 Formulas for calculating a distance in kilometers to a distance in latitude and longitude
+lat = distance_in_km/111.32km
+lng = (distance_in_km × 360)/(40075km × cos(lat))
+
+'''
+
 
 # Read a json file with relation data and send to response object
 def cut_map(self, cursor, lake_name: str):
@@ -22,10 +37,12 @@ def cut_map(self, cursor, lake_name: str):
 
         divided_map = []
 
-        for polygon in polygons:
-            cell_width = 0.04
-            cell_height = 0.02  # NB could be calculated based on cell_width and distance from equator
+        dist_in_km = 0.08  # NB placeholder
+        cell_size = dist_in_km * 10
+        cell_width = cell_size / 111.32
+        cell_height = (cell_size * 360) / (40075 * cos(cell_width))
 
+        for polygon in polygons:
             lines = create_grid(polygon, cell_width, cell_height)
             lines.append(polygon.boundary)
             lines = unary_union(lines)
@@ -79,6 +96,8 @@ def cut_map(self, cursor, lake_name: str):
                 INSERT INTO BodyOfWater(Name) VALUES (?);
             ''', (lake_name,))
 
+        plot_map(divided_map)
+
         write_json_to_file(lake_name, feature_collection)
 
         self.send_response(200)

server/map_handler/lake_relations/all_lake_names.json

 [
-  "Mj\u00c3\u00b8sa",
-  "Skumsj\u00c3\u00b8en"
+  "Mjøsa",
+  "Skumsjøen",
+  "Gjersjøen",
+  "Gjersjøen",
+  "Skumsjøen"
 ]
\ No newline at end of file