diff --git a/hydra_base/lib/network.py b/hydra_base/lib/network.py
index 7566a358..86e4e809 100644
--- a/hydra_base/lib/network.py
+++ b/hydra_base/lib/network.py
@@ -1783,6 +1783,15 @@ def get_network_extents(network_id,**kwargs):
         # Default y extent if all None values
         min_alt_y, max_alt_y = 0, 1
 
+    # min/max default to fake 0/1 (or 0/100 in some callers) ranges when a
+    # coordinate system has no data at all, which the frontend can't tell
+    # apart from "genuinely spans 0 to 1" - these booleans let it reliably
+    # detect presence instead (see hwi's network.html: hasGeographicView/
+    # hasSchematicView, which gate whether the map/schematic view - and the
+    # dual-view switch button - are offered at all).
+    has_geographic = len(x) > 0 and len(y) > 0
+    has_schematic = len(alt_x) > 0 and len(alt_y) > 0
+
     ne = JSONObject(dict(
         network_id = network_id,
         min_x=x_min,
diff --git a/hydra_base/lib/project.py b/hydra_base/lib/project.py
index d49f17b5..ceb6e356 100644
--- a/hydra_base/lib/project.py
+++ b/hydra_base/lib/project.py
@@ -198,6 +198,33 @@ def update_project_appdata(project_id, key, value, **kwargs):
 
     return appdata
 
+@required_perms('edit_project')
+def update_project_appdata(project_id, key, value, **kwargs):
+    """
+        Update a single key in a project's appdata, without touching any
+        other project fields (name, description, parent_id, etc).
+        Unlike Network.appdata (a Text column, manually JSON (de)serialized -
+        see update_network_appdata), Project.appdata is a native JSON column,
+        so no json.dumps/loads is needed here.
+    """
+    user_id = kwargs.get('user_id')
+
+    proj_i = _get_project(project_id, user_id, check_write=True)
+
+    if proj_i.appdata is None:
+        appdata = {}
+    else:
+        appdata = proj_i.appdata.copy()
+
+    appdata[key] = value
+    proj_i.appdata = appdata
+
+    db.DBSession.flush()
+
+    Project.clear_cache(user_id)
+
+    return appdata
+
 @required_perms('edit_project')
 def move_project(project_id, target_project_id, **kwargs):
     """
diff --git a/tests/test_network.py b/tests/test_network.py
index dc4dd0cd..f6e9aae3 100644
--- a/tests/test_network.py
+++ b/tests/test_network.py
@@ -301,6 +301,77 @@ def test_get_extents(self, client, network_with_data):
         assert extents.max_x == 100
         assert extents.min_y == 9
         assert extents.max_y == 99
+        assert extents.has_geographic is True
+        assert extents.has_schematic is True
+
+    def test_get_extents_empty_network(self, client, projectmaker):
+        """
+        A network with no nodes at all has no coordinates in either system.
+        """
+        project = projectmaker.create('test')
+
+        network = dict(
+            name = 'Network @ %s'%datetime.datetime.now(),
+            description = 'Test network with no nodes',
+            project_id = project.id,
+            links = [],
+            nodes = [],
+            layout = {},
+            scenarios = [],
+            resourcegroups = [],
+            projection = None,
+            attributes = [],
+        )
+        network = client.add_network(network)
+
+        extents = client.get_network_extents(network.id)
+
+        assert extents.min_x is None
+        assert extents.max_x is None
+        assert extents.min_y is None
+        assert extents.max_y is None
+        assert extents.has_geographic is False
+        assert extents.has_schematic is False
+
+    def test_update_network_appdata(self, client, network_with_data):
+        """
+        Test that a single key can be set in a network's appdata without
+        touching any other network fields, and that the result persists.
+        """
+        net = network_with_data
+
+        newappdata = client.update_network_appdata(net.id, 'dualViewEnabled', True)
+
+        assert newappdata['dualViewEnabled'] is True
+
+        # Setting a second key should not clobber the first.
+        newappdata = client.update_network_appdata(net.id, 'schematicGridSize', 25)
+
+        assert newappdata['dualViewEnabled'] is True
+        assert newappdata['schematicGridSize'] == 25
+
+        updated_net = client.get_network(net.id)
+        persisted_appdata = json.loads(updated_net.appdata)
+
+        assert persisted_appdata['dualViewEnabled'] is True
+        assert persisted_appdata['schematicGridSize'] == 25
+
+    def test_update_network_appdata_no_permission(self, client, projectmaker, networkmaker):
+        """
+        A user with no write access to a network's project must not be able
+        to update its appdata.
+        """
+        # Create a project that is NOT shared with other users
+        private_proj = projectmaker.create(name=None, share=False)
+        net = networkmaker.create(project_id=private_proj.id)
+
+        # UserD has not been granted access to this private network/project
+        client.login('UserD', 'password')
+        try:
+            with pytest.raises(hb.exceptions.HydraError):
+                client.update_network_appdata(net.id, 'dualViewEnabled', True)
+        finally:
+            client.login('root', '')
 
     def test_update_network_appdata(self, client, network_with_data):
         """