Begin with Location tree.

eraser-base/src/main/jastadd/Location.jrag

+aspect Location {
+  syn Optional<Location> Item.myLocation() {
+    if (this.hasLocation()) {
+      return Optional.of(this.getLocation());
+    } else {
+      return JavaUtils.ifPresentOrElseReturn(linkedThing(),
+          thing -> thing.hasLocation() ? Optional.of(thing.getLocation()) : Optional.empty(), () -> Optional.empty());
+    }
+  }
+}

eraser-base/src/main/jastadd/Location.relast

+Location ::= <Label:String> SubLocation:Location ;
+rel Location.Thing* <-> Thing.Location? ;
+rel Location.Item* <-> Item.Location? ;

eraser-base/src/main/jastadd/Navigation.jrag

@@ -124,6 +124,16 @@ aspect Navigation {
   inh NeuralNetworkRoot OutputLayer.containingNeuralNetwork();
   eq NeuralNetworkRoot.getOutputLayer().containingNeuralNetwork() = this;
 
+  //--- linkedThing ---
+  syn Optional<Thing> Item.linkedThing() {
+    if (!this.hasChannel()) {
+      return Optional.empty();
+    }
+    Channel channel = this.getChannel();
+    Thing thing = channel.containingThing();
+    return Optional.of(thing);
+  }
+
   //--- getRoot ---
   inh Root ASTNode.getRoot();
   eq Root.getChannelCategory().getRoot() = this;

eraser-base/src/main/jastadd/main.relast

 // ----------------    Main    ------------------------------
 Root ::= Thing* Group* ThingType* ChannelType* ChannelCategory* ItemCategory* User* MqttRoot InfluxRoot
-         MachineLearningRoot Rule* ;
+         MachineLearningRoot Rule* Location* ;
 
 // ----------------    Users   ------------------------------
 User : LabelledModelElement ;