Introduction to Data Visualisations

Published on Oct 01, 2016

When we think about urban metabolism and other urban environmental assessments, we often think about numbers, data analysis, formulas and tables. While we may be very familiar with our own case study, it is often very difficult for share their relevance of our results with other researchers or with the general public.

The fact is that in order to describe the metabolism of cities, it is often necessary to look for data over a number of academic and grey literature sources.  However, it can be very difficult to synthesise all this amount of knowledge into something easy to grasp.  This is one of the main reasons why, researchers, use visualisation techniques. Visualising data can not only enable to summarize big amount of numbers, but it can also make it easier share them and use them as policy instruments.

But, which visualisation technique fits best for which type of results? Which software or application is best for each type of dataviz? What font, what colour should be used? And the list of questions goes on. In fact, a bad visualisation can be extremely confusing and repelling. Instead of helping to convey your message a bad visualisation can lead to losing all the interest of your audience.

What type of visualization should I choose?

 
A lot of work has already been done in the field of data visualisation that is very applicable to urban metabolism. Some great and inspiring examples of visualisations can be found here:

• http://tulpinteractive.com/
• http://flowingdata.com/
• http://alignedleft.com/work
• https://github.com/d3/d3/wiki/Gallery
  

Of course, most of them are done by people that specialise in data visualisation and these examples can seem out of reach. Nevertheless there are some hints and tips that are useful for all of us when thinking about visualising our results. Firstly, we need to know what you want to show with your results. The following diagram gives you an easy way to choose among different types of visualisation.

Source: http://www.verstaresearch.com/types-of-charts.jpg
 
Perhaps a more elaborate and extensive diagram of Severino Ribecca that enables us to choose from different visualisation methods depending on what we want to show is the following:

Source: http://www.datavizcatalogue.com/search.html
 
In this diagram, you can click on each of the possible ways to illustrate your results and it will provide you with all the visualisation methods that are relevant. A full list of all the visualisation methods available are presented here below:

Once again, you can click on each of the visualisation methods and it will redirect you to a more thorough description of the latter as well as giving already made examples as well as the tools that will help you to generate this visualisation method.
 

Which software should I use?

The question that get most frequently asked when we look at a beautiful visualisation is, what software did you use. There is a myriad of softwares out there, from the most simple that can be relatively good to represent a couple of visualisation methods to extremely complicated that can carry out and customize all of them. Some of these tools are:

• PowerPoint
• D3.js
• Illustrator and  Photoshop (Adobe Suite) or Inkscape and Gimp (free software)
• Arcgis or Qgis
• Python (library ggplot2)
• R
• Tableau
• http://raw.densitydesign.org/
• http://sankeymatic.com/

One important distinction that you have to make is that some of these tools are relatively easy to use but can have limited options (PowerPoint, Photoshop, Gimp, Arcgis, Qgis, Tableau, etc.) and some other require that you know some sort of coding in order to fully customize and control every single aspect of your illustration.
 

Some examples?

One very famous example of visualisation in the field of urban metabolism and urban environmental assessment is the one Duvigneaud and DeSmet 1977. In it, the authors have successfully summarised a great amount of figures describing the environmental flows of Brussels’ ecosystem. The authors have not only managed to create a single graphic with all this information but this visualisation remains very legible and intriguing.

A number of other visualisation related to material flow analysis can be found at the blog of Nels Nelson. Some other examples of interactive visualisation done by the urban metabolism community are:

• http://www.materialflows.net/visualisation-tools/mfa-map
• http://www.energyatlas.ucla.edu