With shockwave theory you can determine the traffic state that you can expect when you have a certain demand profile, so the fundamental diagram can be determined at all location of the roadway segment you are analysing. How to do this is extensively explained in this lecture. Some applications will be given; temporary over-saturation of a bottleneck and a temporary blockade, like a traffic light or a open bridge.  These applications are on the slides but not on collegerama. Lastly the lecture  discusses factors that influence how a fundamental diagram looks like, therefore it is explained how the shape of the fundamental diagrams can be based on data.