September 13th, 2005

The first figure (source here) illustrates the loss of Pacific salmon habitat, which compares the pre-1900 and present extents of salmon and steelhead spawning and rearing habitat within the Columbia River Basin.

In my opinion, this is not a good visualization. The biggest problem of it is that reader may feel confused by the overlap area of the Historic Distribution and Present Distribution. In addition, it seems not accurate enough for us to know whether a specific part of a state (ex. a city) is in some area or not.

The second figure (source here) shows the fisheries activities in the Bay of Biscay.

It is a good visualization because we can easily understand what it means without author¡¯s explanation. We could find at least two advantages it has compared with the first visualization. First, it leverages multiple colors which can contain more information than black and white pattern. Second, putting grid on the graph makes it more clarified and accurate. In addition, containing not too much stuff makes it easy to understand.