It’s easy to find critiques of bad graphs (just ask Google), so I’d like to comment on a good graph. The Orange Water and Sewer Authority does a great job of posting graphs of water supply and demand. The graphs are not especially pretty, but they do a good job of showing the data and have helpful legends.
The third “graph” is the real gem. (It’s not really a graph â€” it’s a decorated spreadsheet.) It shows a lot of information in a fairly approachable format. The colors represent water conservation stages associated with a given reservoir level and month. It’s easy to see that a 60% full reservoir is something to worry about in June but not a real danger in January. And for comparison, the graph also shows the levels during the 2002 drought, last year, and this year.
OWASA was kind enough to share the data with me, and here is my attempt at a prettier version of the graph.
The original graph has its share of graphic shortcomings, but it still makes for an insightful look at the data. Shortcomings:
- some cells on the border between green and striped are miscolored, according to the legend
- there’s too much detail (don’t need both counts and percents, for example)
- it’s too small to read all of the numbers
- the stripe pattern doesn’t work well over text
- the overall presentation is too chunky (due to spreadsheet limitations) for the continuous data
My version addresses those shortcomings but has some of its own, mostly due to my app limitations:
- x axis uses numbers instead of month names
- y axis uses fractional numbers instead of percents
- no title or legends
- stray horizontal line across the top
- missing some data, such as average monthly water usage