While this website is not strictly related to urban ecosystems, urban ecology or urban metabolism, it shows a very interesting way of how to visualise energy, greenhouse gases, materials, water and waste flows.
Inside this website you can find a large number of case studies.
For instance, the following one shows a study from the EEA about the energy flows across the EU-28 states in 2012 (expressed in Mtoe).
This next one shows in turn the trade flows of oil and oil products flows (coming from GEA Global Energy Assessment 2012– Toward a Sustainable Future, Cambridge University Press, Cambridge UK and New York, NY, USA and the International Institute for Applied Systems Analysis, Laxenburg, Austria)
Bethléem Ecosystème 