Using symbols to represent data can increase impact and understanding of the underlying data. In this post, I’ll discuss some best practices for doing this successfully in charts, maps, and diagrams.
The following weather symbols are used to show drizzle, rain, and snow a. The symbols look roughly like drizzle, raindrops, and snowflakes:
They are combined in consistent manner and an analogy of the physical process they are describing:
- More symbols mean light, medium or heavy
- Symbols that are stacked vertically mean intermittent, while horizontal mean continuous.
These symbols work because they look somewhat like the condition they are describing so it is somewhat intuitive (and memorable) what the symbls are talking about.
Here’s another example of symbols, this time fairly cryptic:
These could be buttons, sieves, pipes. It’s difficult to understand their meaning. Even knowing their location (a label on clothing) doesn’t make it apparent. The symbols represent a dryer and the colorings represent no heat, low heat, medium, high heat, and any heat. These are somewhat inconsistent as you might expect the filled black circle to be “highest heat” and the blank circle to be “no heat”. Here’s the entire set:
These are fairly complex symbols for the dryer with lines below indicating normal, permanent press, and delicate, but the order might be expected to be reversed: no lines = delicate, 1 line = permanent press and 2 lines for normal (with the line indicating “more vibration”.
All in all, the fabric care symbols are more complex, less consistent, and more difficult to understand.
Here are some thoughts on how to use symbols effectively in charts and diagrams:
- Use simple symbols that are readily understood
If possible, the symbols should suggest or relate to the actual quantity they are describing. If needed, add numbers or words oto help the meaning, if not relatively apparent.
- Provide a legend for what the symbols mean
A clear legend explaining the meaning of individual symbols is helpful; some explanation of the rationale can also help. (ie what thinking went into the specific shapes or combinations)
- Be consistent in how the symbols are combined and used
Develop a “grammar” of how the symbols are combined. For example, with the weather symbols, more symbols means “heavier”; for the laundry symbols, more dots means “hotter temperature”. If you are trying to add another dimension (intermittent vs. continuous, slower speeds vs. higher), be consistent in combining them. especially across different symbol sets. The weather symbols are very consistent across drizzle, rain, and snow. (there’s also a combination rain and snow symbol for sleet)
- Test the symbols on a wide variety of users
Test out the symbols and see if they are intuitive and help the user understand the chart or diagram. If not, modify them owhere ambiguous or confusing r increase training and user aids (legends, guides) to make them more easily understood.