Documentation-of-the-Knowledge-Graph.md

@@ -77,6 +77,14 @@ Computing coordinates in different frames of reference can be done in 2 dimensio
 
 The device has coordinates relative to the factory that are computed as follows: $`x'_{\text{factory}} = x'\text{cos}(\alpha) + y'\text{sin}(\alpha)`$ and $`y'_{\text{factory}} = -x'\text{sin}(\alpha) + y'\text{cos}(\alpha)`$. In 3D, we provide an additional angle representing the tilt of the *Z* axis with respect to the *XY* plane.
 
+The following two diagrams give the different coordinates systems of the ITm factory workshop:
+
+![itm-coords](uploads/d51b1cd119d7f8dfbce9cfca7e2f0eb4/itm-coords.png)
+
+and the coordinates of important points of the different workshops, with the factory floor's origin as reference:
+
+![itm-pois](uploads/508d42bcfc8fd40cc8b009bd2014b8a6/itm-pois.png)
+
 ## Relations between sensing/actuating devices, observable/actuatable properties, and property/action affordances
 
 We can relate properties of the real world, devices that sense or act upon those properties, and the thing APIs that can get access to the observations or actions of/on these physical properties. For this, we are using the [SOSA/SSN ontology](https://www.w3.org/TR/vocab-ssn/). In particular, this allows one to determine what sensor observes a certain property of a particular feature of interest. In the case of the production line, we may want to distinguish the presence sensor at the beginning of a conveyor belt and at the one at the end. These observe presence at different locations, that are identified in the knowledge graph. The following diagram shows how this is done for the input and output areas of the filling workshop.