diff --git a/uvdat/core/models/networks.py b/uvdat/core/models/networks.py
index 8f4ef129..6a83b1cc 100644
--- a/uvdat/core/models/networks.py
+++ b/uvdat/core/models/networks.py
@@ -21,6 +21,8 @@ def get_graph(self):
     def get_gcc(self, exclude_nodes):
         graph = self.get_graph()
         graph.remove_nodes_from(exclude_nodes)
+        if graph.number_of_nodes == 0 or nx.number_connected_components(graph) == 0:
+            return []
         gcc = max(nx.connected_components(graph), key=len)
         return list(gcc)
 
diff --git a/uvdat/core/rest/chart.py b/uvdat/core/rest/chart.py
index 794b3373..a7ec8700 100644
--- a/uvdat/core/rest/chart.py
+++ b/uvdat/core/rest/chart.py
@@ -12,7 +12,8 @@ class ChartViewSet(GenericViewSet, mixins.ListModelMixin):
     serializer_class = ChartSerializer
 
     def get_queryset(self, **kwargs):
-        context_id = kwargs.get('context')
+        request = self.request
+        context_id = request.query_params.get('context')
         if context_id:
             return Chart.objects.filter(context__id=context_id)
         return Chart.objects.all()