[ project energyflow ]


Project "Energieflussdiagramme"

Every city needs energy in various forms like gas or oil. The energy gets distributed within the city and is transformed into heat or electricity, for example. Those energies are going to propel the citizens electrical devices, heat their houses and move their cars.

As time passes by and energy technologies evolve, the energy footprint of a city changes. The main points of interest are questions like how the energy is distributed, where are the hugest losses and what kind of energy is used for which purpose.

In other words engineers are interested in the specific energy flow of a city. Typically, the underlying dataset is a spreadsheet that constists of thousands of values and equations which in a whole describe the energy flow network.

This is a representation that is very hard to interpret and to deal with. Especially when less involved people want to have an insight. Those people can be normal citizens that just want to inform themselves. The managment staff of an energy company wants to discover trends in the energy market to optimize their business. Politicians must have an overview of the energy structure of a city, because they have to make decisions: What part of the energy structure could be changed, for example to minimize carbone-dioxid emissions?

To support the understanding of the energy structure, the data is visualized in special diagrams, the so called sankey-diagrams. These diagrams represent the energy flow as a graph and the particular amount of energy as thickness of the edges. Usually the diagrams are assembled by hand which is an arduously and error prone work.

Therefore, society could greatly benfit from a tool that creates interactive and dynamic sankey-diagrams automatically, to ease the interpretation an exploration of energy strutures, leading to a better understanding. The creation of such a tool is the aim of this project.

The tool that we have developed is splitted into a modeling and a rendering component. The modeling component is a graph editor which is used to specify the dependencies and values of the energy flow and furthermore sets some rendering hints. The output of the modeler is then visualized by the renderer. Additionally the renderer serves as the user interface to make interactions with the sankey-diagram possible.

Popup menus for detailed information on components of the sankey-diagram are supported. Edges can be selected and promoted to the foreground to improve the readability if necessary. Focus and context is used for zooming and navigation.

A lot of work still has to be done in the field of level of detail for the diagrams. When zooming in, there is more space for detailed information. And a broad view of the sankey-diagram should hide most of the details to improve readability. Another important aspect that has not been dealt with yet is the visualization of the energy structures' changes over several years. Additionally one has to find a way to visualize the small changes in the energy structure that have a big impact on the schadstoff emissions.

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  © 2004 · Patrick Riehmann, Moritz Goellner, Henrik Thoms · Emailemail