Design Pattern: RM(11) Bar Charts


A set of incoming alarms has been registered. The human operator would like to compare the number of alarms across different dimensions such as priority, typology or time.


The human operator needs to compare the number of alarm activations across alarm dimensions.


Use bar charts to represent absolute magnitudes of alarm activations. A bar chart is graphic figure in which numeric quantities are represented by the linear extent of parallel lines or bars, either horizontally or vertically. They can theoretically consist only a single data item, but in most cases are used to additionally compare the quantitative value of several entities with each other. All data items are measure on the same scale.

Known uses
Fig1. DeltaV system alarm statistics page (see a bar chart for alarm activation rates per device framed in red)
Fig2.IrisView system alarm dashboard which gives the operator a view of any alarms associated with the elements they are responsible for (see a bar chart for alarm activation rates per device framed in red)

Bar charts are, besides pie charts the most common data visualization technique and find wide usage in popular statistics [13]. They are useful to compare several quantitative entitles of a common class. (Card, S. K., Mackinlay, J. D., & Shneiderman, B. (1999). Readings in information visualization: Using vision to think Morgan Kaufmann Pub. )