Figure 4.1. Global Flows of E-waste for the year 2012 (click here to launch the cartogram in a full browser window).
This cartogram depicts data available from the United Nations Statistics Division's "COMTRADE" database. The data are organized into territories and the flows of e-waste that connect them. Territories are color coded by continent. The larger the circle representing a given territory (e.g., Canada) the more other territories report receiving e-waste shipments from it.
The flow lines depict the volume and direction of e-waste flows between territories. They are color coded to reflect their source territory. To understand flow direction, follow flow lines in a clockwise direction from one node to another. The thicker the flow lines, the larger the volume of the flow. Currently the software used to create the cartograms (discussed below) does not easily allow labeling of the flows (i.e., displaying the actual number representing the weight of the flow volume).
The data come with some extremely important caveats and limits. These are discussed fully in the Methods section of Lepawsky (2015). In summary, the caveats and limits of the data include:
- The data show information only for "waste batteries and scrap of primary batteries and electrical accumulators" (technically referred to as Harmonized System 2002 code 854810).
- The data are import transactions reported by a given territory. In other words, these are data showing what Territory "A" says it receives as an import from another territory or territories in a given year (e.g., from Territories "B", "C", and "D").
- The data miss unreported trade (whether licit or illicit).
- The data visualized here are best understood as proxy measurements of overall transboundary shipments of electronic discards.
To view the cartograms, move your mouse over one of the cartograms and click the "Source" button when it appears beneath it. This will open the cartogram in a full sized window (they do not have full functionality on mobile platforms). Also:
- Ensure that you have the latest version of java and an up to date browser running.
- Hover the mouse over a cartogram. When you see the option for "Source" appear beneath the cartogram, click on it. This will launch the cartogram in a full browser window.
- In the full cartogram you can click a given territory (e.g., Canada) and its trade network will be highlighted and a side-bar with additional information will pop-up.
- Read flow lines in a clockwise direction from a given territory to the territory(ies) that report receiving shipments of e-waste from it.
- Data were downloaded from COMTRADE and organized in a spreadsheet.
- The organized data were imported into Gephi, a free open-source network analysis software.
- The networks created in Gephi were exported using Sigmajs Exporter, a Gephi plugin produced by the Oxford Internet Institute.
The Gephi networks exported using Sigmajs Exporter currently have some limitations that control the 'look' of the cartograms. These are largely aesthetic, but do have some implications for interpreting the cartograms. For example, it is not currently possible with Sigmajs Exporter to display the value of trade flows (e.g., with a data value adjacent to a given flow line). Thus interpretation of trade volumes is currently limited to visual comparisons of flow line thickness (thicker lines equal greater volumes of flow and vice versa). Also, some flow line colors render inconsistently. This is an artefact of the Sigmajs Exporter plugin and amounts to an aesthetic issue and should not be interpreted as having anything to do with the underlying data.