diff --git a/voegelsberg/import_tachymeter_observations.py b/voegelsberg/import_tachymeter_observations.py
index 4ed9b35..8851712 100644
--- a/voegelsberg/import_tachymeter_observations.py
+++ b/voegelsberg/import_tachymeter_observations.py
@@ -2,6 +2,7 @@
 import csv
 # import requests
 from datetime import datetime
+from typing import List
 import uuid
 from pyproj import Transformer
 # from insert_sensor.wrapper import (Offering, FoI, Procedure)
@@ -101,10 +102,11 @@ def main():
             # pg_session.commit()
 
         # for loop sensors end
+        actualize_first_last_observations()
         pg_session.close()
 
 
-def create_observation(location_dataset: Dataset, data: dict[any, any],  pg_session: session):
+def create_observation(location_dataset: Dataset, data,  pg_session: session):
     ''' create observation in db'''
     # print("Sesnor key exist in JSON data")
     transprojr = Transformer.from_crs(31254, 4326, always_xy=True)
@@ -146,6 +148,46 @@ def create_observation(location_dataset: Dataset, data: dict[any, any],  pg_sess
         return False
 
 
+def actualize_first_last_observations():
+    ''' iterate throug all datasets of Voregelsberg project area 
+        and actualize last and first corresponding observations'''
+    pg_session: session = create_pg_session()
+    platform_sta_identifier = "voegelsberg_tachymeter"
+    # sensor_platform = pg_session.query(Platform.id) \
+    #                 .filter(Platform.sta_identifier == platform_sta_identifier) \
+    #                 .first()
+
+    voegelsberg_datasets: List[Dataset] = []
+    voegelsberg_datasets = pg_session.query(Dataset) \
+        .join(Procedure) \
+        .join(Phenomenon) \
+        .join(Platform) \
+        .filter(Platform.sta_identifier == platform_sta_identifier).all()
+
+    for location_dataset in voegelsberg_datasets:
+        ''' iterate throug all datasets of Voregelsberg project area 
+        and actualize last and first corresponding observations'''
+        last_location_observation = pg_session.query(Observation) \
+            .filter(Observation.fk_dataset_id == location_dataset.id) \
+            .order_by(desc('sampling_time_start')) \
+            .first()
+        if last_location_observation is not None:
+            location_dataset.last_time = last_location_observation.sampling_time_start
+            # location_dataset.last_value = last_location_observation.value_quantity
+            location_dataset.fk_last_observation_id = last_location_observation.id
+        
+        first_location_observation = pg_session.query(Observation) \
+            .filter(Observation.fk_dataset_id == location_dataset.id) \
+            .order_by(asc('sampling_time_start')) \
+            .first()
+        if first_location_observation is not None:
+            location_dataset.first_time = first_location_observation.sampling_time_start
+            # roll_dataset.first_value = first_location_observation.value_quantity
+            location_dataset.fk_first_observation_id = first_location_observation.id
+
+        pg_session.commit()
+
+
 def get_xml(offering, procedure,  foi, result_time, identifier):
     '''  """
     Prepares the body of a InsertSensor request for JSON biding.
@@ -178,4 +220,4 @@ def get_xml(offering, procedure,  foi, result_time, identifier):
 
 
 if __name__ == '__main__':
-    main()
+    actualize_first_last_observations()