fix bug year

dash/pages/sample-tracker.py

@@ -553,13 +553,11 @@ def updateMap(clustering_name,colorizingmap_name,tiles):
     
     
     species_colors = {}
+    df_geo['Year'] = df_geo['Sampling_date'].dt.strftime('%Y')
     list_of_species = df_geo['Species'].unique().tolist()
-    list_of_years = df_geo['Sampling_date'].unique().tolist()
-    dict_year = {}
-    for y in list_of_years:
-        dict_year[y.year]=1
+    list_of_years = df_geo['Year'].unique().tolist()
     
-    sorted_years = sorted(list(dict_year.keys()))
+    sorted_years = sorted(list_of_years)
     predefined_colors = list(mcolors.CSS4_COLORS.keys()) 
 
     legend_html = '''