Stanford University has a variety of data visualizations on their Spatial History page, and this post looks at a couple of them to comment on the design choices.
First is the Historic Quad Index, found at
https://web.stanford.edu/group/spatialhistory/cgi-bin/site/viz.php?id=7&project_id=
This visualization is in the form of a map, or as described in its description, a “georeferenced shapefile,” showing the United States Geological Survey’s quadrangles. This visualization assumes the viewer knows something about USGS quads, as this is not explained in the about section. It specifies that “the largest rectangles are 60 minute quads and the smallest are 7.5 minutes quads,” but again assumes the viewer knows what that means. Without more information, it is difficult to know what argument this visualization is making.
As seen in the above image, the quads are displayed in different colors, but there are a couple issues with the design choices in this regard. 1) no legend is included to specify which color corresponds to what. The description only says that “the different colors represent the different scales of USGS quads,” but not what those different scales are. 2) the yellow color is difficult to distinguish from the slightly lighter and more greenish yellow, especially where the two are not right next to each other.
The second visualization, this one displaying the Cattle Production in the American West, is more interactive, and is found at
https://web.stanford.edu/group/spatialhistory/cgi-bin/site/viz.php?id=7&project_id=
Like the last one, the data is laid out geographically on a map, and changes according to the year selected on the interactive date scale at the bottom. The assumption of viewer knowledge is lower, and the data tells a story of the vacillations in cattle producing regions and the value of cattle in these areas. Specifically, Texas becomes a focus due to the size of its circle (somewhat misleading), and maintains that focus even as other areas expand their cattle production, as shown in below images.
Data is shown in circles corresponding to states that produced cattle in a given year, and also in a bar chart broken down by region and state. Both the circles and bars are colored to show the value of the cattle, and the size of the circles represent how many cattle there were. Here is introduced on flaw, i.e. that, as seen in the scale, the circle for 4 million cattle looks to be four times bigger than the circle for 2 million, and four times smaller than that for 7 million.
While some of the Standford spatial visualizations link to the data used, neither of these to did so.