diff --git a/measprocess/data_extractor.py b/measprocess/data_extractor.py
index f6c6996b688b74d8c519b0bdd0f778814cc2e525..295f2a3a674fb1e7a493613481c849ed68733007 100644
--- a/measprocess/data_extractor.py
+++ b/measprocess/data_extractor.py
@@ -19,6 +19,8 @@ def fetch_rtr_details(open_test_uuids: List[str]) -> List[dict]:
     """
     Fetch test details from RTR-Opendata for a list of open_test_uuids.
     These open_test_uuids can for instance be obtained via data_extractor.fetch_rtr_overview()
+    Detailed information about the API endpoint and the meaning of returned parameters is available under:
+    https://www.netztest.at/en/OpenDataSpecification.html.
 
     :param open_test_uuids: List of open_test_uuids for which test details will be fetched
 
@@ -55,20 +57,29 @@ def fetch_rtr_overview(
     raw_params: List[Tuple[str, str]] = [],
 ) -> pd.DataFrame:
     """
-    #Todo work on documentation! --> cat_technology, also filter not nan filters, test raw parameters
+    Queries the RTR-Netztest API according to the passed filters.
+    Detailed information about the API endpoint and the meaning of returned parameters is available under:
+    https://www.netztest.at/en/OpenDataSpecification.html.
+    Comprehensive results for each test can be obtained by passing the
+    open_test_uuids of the fetched measurements to fetch_rtr_details.
 
-    raw params are a list of parameters that will be concateneated and passed to the request
+    :param time_min: Lower bound for time-filter. Passed Datetime objects will be interpreted as UTC.
+    :param time_max: Upper bound for time-filter. Passed Datetime objects will be interpreted as UTC.
 
-    An examplary raw filter would be "cat_technology=4G"
-    Detailed information about the possible filters is available under: https://www.netztest.at/en/OpenDataSpecification.html
+    :gps_boundaries: GeoSeries in EPSG:4326 of the boundaries to filter for.
+    :cat_technology: CatTechnology to filter for. Examples are 3G and 4G.
+
+    :max_results: Upper limit of measurements to fetch.
+
+    :raw_params: Passed raw parameter tuples will be appended to the request url as key, value pairs.
+
+    :return: A pandas dataframe consisting of all the fetched measurements.
     """
 
     url = f"{BASE_URL}/{SUBDOMAIN_OVERVIEW}"
     request_params = MultiDict()
 
-    """
-    Build request params
-    """
+    #Build the request parameters
 
     if gps_boundaries is not None:
         if gps_boundaries.crs != "EPSG:4326":
diff --git a/measprocess/geospatial.py b/measprocess/geospatial.py
index 58ff7e3d130e27078f01eb8aec56046ae630e8e1..b01f931f3499997aa9f88d98d9756a7bd714695b 100644
--- a/measprocess/geospatial.py
+++ b/measprocess/geospatial.py
@@ -118,14 +118,32 @@ def project_onto_streets(
     plot: bool = False,
 ) -> (gpd.GeoSeries, gpd.GeoSeries):
     """
-    Todo: Not completed
+    Projects each point from the point_series onto the closest element of
+    street_series according to a normal projection. For that, both
+    series will be transformed into a 2D projection (default EPSG:31287).
+
+    :param point_series: GeoSeries of all points to project onto streets.
+    :param street_series: GeoSeries of linestrings representing the streets.
+    :param epsg: EPSG projection to use during the projection operation.
+    :param plot: Boolean to indiceate whether the result of the operation shall be plotted.
+
+    :return: A tuple of two GeoSeries containing the result of the operation as well as the deviation introduced.
     """
 
-    if point_series.crs != epsg or street_series.crs != epsg:
+    if epsg == "EPSG:4326":
         raise ValueError(
-            "GeoSeries does not match value set by epsg argument (Default EPSG:31287)"
+            "Projection cannot be conducted using geographical coordinates such as EPSG:4326. Select 2D projection instead."
         )
 
+    if point_series.crs is None or street_series.crs is None:
+        raise ValueError(
+            "CRS needs to be set explicitly for passed Geoseries: Use .set_crs()."
+        )
+
+    point_original_crs, street_original_crs = point_series.crs, street_series.crs
+    point_series = point_series.to_crs(epsg)
+    street_series = street_series.to_crs(epsg)
+
     projected = []
     for point in point_series:
         street_ind = street_series.distance(point).argmin()
@@ -161,6 +179,11 @@ def project_onto_streets(
         ax2.legend()
         plt.show()
 
+    #Reset Street and Point Series CRS
+    street_series.to_crs(street_original_crs)
+    point_series.to_crs(point_original_crs)
+    projected.to_crs(point_original_crs)
+
     return projected, deviation_projection
 
 
diff --git a/tests/projection_test.py b/tests/projection_test.py
index 21bd5efe93ae7b1a2e38a727091cc6349f8825ee..375671254fdd1c2836b5672e451eb37e43435d68 100644
--- a/tests/projection_test.py
+++ b/tests/projection_test.py
@@ -31,11 +31,12 @@ class TestProjections(unittest.TestCase):
 
     def test_other_projection(self):
         mpc.geospatial.project_onto_streets(
-            self._point_series.set_crs("EPSG:3416"),
-            self._street_series.set_crs("EPSG:3416"),
-            epsg="EPSG:3416"
+            self._point_series.set_crs("EPSG:4326"),
+            self._street_series.set_crs("EPSG:4326"),
+            epsg="EPSG:31287"
         )
 
+
     def test_exception_epsg(self):
         with self.assertRaises(ValueError):
             mpc.geospatial.project_onto_streets(
@@ -44,10 +45,11 @@ class TestProjections(unittest.TestCase):
                 epsg="EPSG:31287"
             )
 
+        with self.assertRaises(ValueError):
             mpc.geospatial.project_onto_streets(
-                self._point_series.set_crs("EPSG:31287"),
-                self._street_series.set_crs("EPSG:31287"),
-                epsg="EPSG:3416"
+                self._point_series.set_crs("EPSG:4326"),
+                self._street_series.set_crs("EPSG:4326"),
+                epsg="EPSG:4326"
             )
 
     def test_basic_projection(self):