diff --git a/mlair/data_handler/iterator.py b/mlair/data_handler/iterator.py
index 39e20020f4f80a872428681d53e2ec9f1a3dd3f7..18466fd9ede1e666f52b49fa461585a7e38410dd 100644
--- a/mlair/data_handler/iterator.py
+++ b/mlair/data_handler/iterator.py
@@ -33,13 +33,18 @@ class StandardIterator(Iterator):
 
 class DataCollection(Iterable):
 
-    def __init__(self, collection: list = None):
+    def __init__(self, collection: list = None, name: str = None):
         if collection is None:
             collection = []
         assert isinstance(collection, list)
         self._collection = collection
         self._mapping = {}
         self._set_mapping()
+        self._name = name
+
+    @property
+    def name(self):
+        return self._name
 
     def __len__(self):
         return len(self._collection)
diff --git a/mlair/plotting/postprocessing_plotting.py b/mlair/plotting/postprocessing_plotting.py
index dc33219055db83012449be56c4071df2177af6e2..2ffeb536cfd1a7fc5094ffa72c23ee8819a324d6 100644
--- a/mlair/plotting/postprocessing_plotting.py
+++ b/mlair/plotting/postprocessing_plotting.py
@@ -10,6 +10,7 @@ from typing import Dict, List, Tuple
 
 import matplotlib
 import matplotlib.patches as mpatches
+import matplotlib.lines as mlines
 import matplotlib.pyplot as plt
 import matplotlib.dates as mdates
 import numpy as np
@@ -279,16 +280,22 @@ class PlotStationMap(AbstractPlotClass):
 
         import cartopy.crs as ccrs
         if generators is not None:
+            legend_elements = []
             for element in generators:
                 data_collection, plot_opts = self._get_collection_and_opts(element)
                 marker = plot_opts.get("marker", "s")
-                ms = plot_opts.get("markersize", 6)
+                ms = plot_opts.get("ms", 6)
                 mec = plot_opts.get("mec", "k")
                 mfc = plot_opts.get("mfc", "b")
+                name = data_collection.name or "unknown"
+                legend_elements.append(
+                    mlines.Line2D([], [], mfc=mfc, mec=mec, marker=marker, ms=ms, linestyle='None', label=name))
                 for station in data_collection:
                     coords = station.get_coordinates()
                     IDx, IDy = coords["lon"], coords["lat"]
                     self._ax.plot(IDx, IDy, mfc=mfc, mec=mec, marker=marker, ms=ms, transform=ccrs.PlateCarree())
+            if len(legend_elements) > 0:
+                self._ax.legend(handles=legend_elements, loc='best')
 
     @staticmethod
     def _get_collection_and_opts(element):
diff --git a/mlair/run_modules/post_processing.py b/mlair/run_modules/post_processing.py
index 0b9393e0ef902d4256bded0e6466d00a6d79910d..300d2e1dbd2ded279ee289ee64a2acd5f5c36fbc 100644
--- a/mlair/run_modules/post_processing.py
+++ b/mlair/run_modules/post_processing.py
@@ -277,8 +277,8 @@ class PostProcessing(RunEnvironment):
                 logging.warning(
                     f"Skip 'PlotStationMap` because running on a hpc node: {self.data_store.get('hostname')}")
             else:
-                gens = [(self.train_val_data, {"mfc": "r", "marker": 8}),
-                        (self.test_data, {"mfc": "b", "marker": 9})]
+                gens = [(self.train_val_data, {"mfc": "r", "marker": 8, "ms": 10}),
+                        (self.test_data, {"mfc": "b", "marker": 9, "ms": 10})]
                 PlotStationMap(generators=gens, plot_folder=self.plot_path)
         if "PlotMonthlySummary" in plot_list:
             PlotMonthlySummary(self.test_data.keys(), path, r"forecasts_%s_test.nc", self.target_var,
diff --git a/mlair/run_modules/pre_processing.py b/mlair/run_modules/pre_processing.py
index c9e92e7deb22dcff12e9d4ab982f14289f764a97..bd3b9ec6fd471dcb6e794a3ba9b498e18ad76a37 100644
--- a/mlair/run_modules/pre_processing.py
+++ b/mlair/run_modules/pre_processing.py
@@ -257,7 +257,7 @@ class PreProcessing(RunEnvironment):
             logging.info("setup transformation using train data exclusively")
             self.transformation(data_handler, set_stations)
         # start station check
-        collection = DataCollection()
+        collection = DataCollection(name=set_name)
         valid_stations = []
         kwargs = self.data_store.create_args_dict(data_handler.requirements(), scope=set_name)