About evolution without progress.

Unless you create the stacked band plot in a web-enabled manner, it suffers the same, in my opinion disqualifying, defect as the stacked bar chart. There is NO way to know reliably the PRECISE value of any band component's measure of interest. In a plot it is the measure at that point in time that you don't know precisely.

Running your eye from two points on plot lines over to the vertical axis, estimating the numbers by visually interpolating between tick mark values, and then mentally subtracting those two estimates is not the path to precise knowledge.

In a chart, plot, graph, infographic, or whatever, you need both image and precise numbers.

Image provides easy, quick inference.
Precise numbers provide reliable, accurate inference.

Web enablement makes precise numbers at least temporarily accessible via pop-up text. For a multi-line or multi-band plot, static annotation is not practical. A companion table is the only choice for non-web information packaging in this kind of visual.

I have my 17-inch laptop set at the recommended resolution, 1920 X 1080. IF I were to change the resolution to, say, 1280 X 720 (still respecting the 16 X 9 aspect ratio, I would get a magnified view. But any visual should by design, be readable for non-exotic viewer without having to take extraordinary measures. The explanatory text of this blog posting is eminently readable. The code font is smaller, but I can still read it. Now to the visuals.

In the plot at the upper right, I can easily read the title and the title of the legend. I CAN read the legend entries, the tick mark values with a bit of visual guessing, but what's in the parenthesis for the vertical axis label I just do not know for sure. If it is ppm for parts per million, whatever are the units could have been added to the chart title.

In the plot at the upper right, I can easily read the title and the title of the legend. I CAN read the legend entries, the tick mark values with a bit of visual guessing, but what's in the parenthesis for the vertical axis label I cannot read. Whatever are the units could have been added to the chart title, and axis label could have been omitted. We read horizontally, not vertically. If no ambiguity, axis labels should simply be omitted, as was the case for the horizontal axis in this case. Often axis identities are already evident from the title, and if still needed, are better placed in a subtitle.

The other problem with that plot is the size of the legend color samples. If the order of the legend entries was not the same as the order of the bands, it would be impossible to know which band is Electrical vs Industrial. Color to be reliably distinguishable must be big enough in area (legend samples or plot markers) or wide enough in thickness (lines and text).

In the plot at the lower left, the associability challenge for the legend was substituted with a readability challenge by putting the labels right into the areas. The resulting problems are text that is too small to easily read (squashed to fit into the narrow bands), and insufficient contrast between the color of the text and the color of the band background. White text would be more readable for some of the bands, especially the blue band, but the font size would still be insufficient. The only worse choice than black on blue is black on black.

I have been sharing advice about the communication-effective use of color with SAS users since 1995. For my latest sharing, see
http://nebsug.org/wp-content/uploads/2016/05/2016-Bessler-Paper-IASUG-NebSUG-2016-Paint-a-Better-Picture-of-Your-Information-with-Color.pdf

I have been advocating for “grouped” bar charts with a total bar in each group, instead of stacked bars, since 1992. See, for example,
http://www.sascommunity.org/sugi/SUGI92/Sugi-92-45%20Bessler.pdf

LeRoy Bessler PhD
Visual Data Insights™
Strong Smart Systems™