Wikipedia Recent Changes Map shows a good example is a good, clean, simple implementation that addresses the question:
“How is Wikipedia being Edited right now?”
Some of the features of this visualization that work:
- Filtered data — the potential data size is huge, and grows as we wait, so the display only shows the most recent events, both on the map and the list below it
- Multiple linked views — data is shown geographically on the world map, and as a list of events below. This is preferable than trying to have one combined view as each view supports a different set of tasks, and combining them would complicate those tasks (WHERE are the changes coming from? WHAT is being changed?)
- Not using graphics — the report on what has changed is a simple scrolling text view; since the dat is textual, and it is ordered, a simple list of text makes sense.
- Different fade-out rates — Using the color for the country to show the most recent changes, and then fading that out in synch with the text description, focuses attention on changes very well. Leaving the dots behind for the changes allows us to keep a longer-term trend in mind.
As a map geek, I might prefer a different projection for the whole earth map; maybe WinkelTripel?
For the Grammar of Graphics language-based approach to visualization, and therefore in the RAVE visualization system, maps are simply another element that can be used within the grammatical formulation.
Although most people consider a map a very different entity from a bar chart, all that really differs between a bar chart and a map of areas like the one included here is that instead of representing a row of data by a bar, we use a polygon (or set of polygons) on a map. Otherwise their properties ought to be the same — we can apply color, patterns, labels, transparency. We can set a summary statistic when there are multiple values for each polygon to reflect min, max, mean, median, range, or any of the regular sets of items. We can flip, transpose and panel the charts. Essentially, from the grammatical point of view, if you can do it to a bar chart, you can do it to a map. The only limitation is that whereas the sizes of the bars can be set or determined by data, the map polygons cannot, so setting sizes on the map polygons has no effect.
Orthogonality is also important — so we can say we want a point element instead of a polygon, as in the above where we’ve added a second element to a RAVE US Map conveying different data as well as being a good place to put labels