Rather than showing flows, this visualization presents stocks of copper in and around the city of Cape Town. Stocks are necessarily linked to a single geographical area (whereas flows from one area to another area, stocks are present in a single area). This makes maps especially suitable for data visualization.

This map makes for a useful visualization that allows instant insight into the copper stocks. The color coding of each area is clear and shows the varying copper intensity throughout the city. One component which may increase understanding, though, is a slightly different color use. Ideally the different intensities are directly linked to the color intensity. If a color is "more red" then this should imply a higher intensity. Here, green is the least intense and red is the most intense. However, the light blue color confuses the reader as to on what intensity this ranks.