diff --git a/server/map/__pycache__/add_lake.cpython-311.pyc b/server/map/__pycache__/add_lake.cpython-311.pyc
index 5791d4e3b431d3b5e9e3a8bfa6f60c3045aaf4dc..7409ca6202d63e1e08f7263c9d2268868485bda9 100644
Binary files a/server/map/__pycache__/add_lake.cpython-311.pyc and b/server/map/__pycache__/add_lake.cpython-311.pyc differ
diff --git a/server/map/get_measurements.py b/server/map/get_measurements.py
index e3f02a6278d383dda372a5ae3850279299d53d40..4199b487bf0b4067e72085c358c23f0957b57766 100644
--- a/server/map/get_measurements.py
+++ b/server/map/get_measurements.py
@@ -1,7 +1,8 @@
 import json
 from datetime import datetime
 import random
-from random import randint
+import geopandas as gpd
+
 
 # get_markers requests all marker data or valid markers, converts the data to json, and writes
 # the data to the response object
@@ -108,8 +109,35 @@ def get_all_markers(self, cursor, waterBodyName):
         ########################### TEST DATA ###########################################
 
         # Convert dictionary values to list of measurements
-        data = list(measurement_data.values()) + test_measurements
+        measurements_list = list(measurement_data.values()) + test_measurements
+
+        ######################### ADD GROUP_IDS TO RELATION DATA ##################################
+
+        # Read lake relation from json file
+        geo_data = gpd.read_file("server/lake_relations/mjosa_div.json")
+        relation_data = geo_data[geo_data['geometry'].geom_type == 'Polygon']
+
+        # Add group IDs to lake relation
+        for measurement in measurements_list:
+            measurement_id = measurement['MeasurementID']  # Extract measurement ID
+            for subdivision in measurement['Subdivisions']:
+                group_id = subdivision['GroupID']  # Extract group ID
+                new_group_id = str(measurement_id) + "-" + str(subdivision['GroupID']) # Create concatenated group ID
+
+                # Find the matching subdivision in relation_data
+                for idx, feature in relation_data.iterrows():
+                    # Add the new group ID to the correct subdivision
+                    if feature['properties']['sub_div_id'] == subdivision['sub_div_id']:
+                        relation_data.at[idx, 'GroupID'] = new_group_id
+
+        ####################################################################################
+
+        # Convert GeoDataFrame to JSON
+        relation_data_json = json.loads(relation_data.to_json())
 
+        # Combine measurements_list and relation_data
+        data = [measurements_list, relation_data_json]
+        
         if len(rows) == 0 or len(data) == 0:  # Return 500 and empty list if no data is found
             print(f"No data which meets the condition found")
             marker_data = '[]'
@@ -126,7 +154,7 @@ def get_all_markers(self, cursor, waterBodyName):
     self.send_header("Content-type", "application/json")
     self.end_headers()
 
-    # Write marker data to response object
+    # Write both measurement data and relation data to the response object
     self.wfile.write(marker_data.encode('utf-8'))