Triangular Graphs

 Triangular Graphs

These are unique garphs that are less common, and generally seen as more complicated, than other graphs. They are useful because they have three axis which means that they can display 3 different variables on the same graph. However the 3 different categories must add up to a total of 100, meaning that these graphs are most widely used to show percentages.

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The graph is always read in a clockwise direction, and any one point will have three values.
For example the graph may be used to show the percentage of people in a country working in the primary, secondary and tertiary sectors of an economy; the values may be 50%, 30% and 20% respectively. The axis on the left hand side of the graph may be labelled as the "Primary Sector" and a mark placed at 50 on the horizontal line extending from this axis. The axis on the right hand side of the graph may be labelled as the "Secondary Sector" and a mark placed at 30 on the line extending diagonally down from this axis. The axis on the bottom may be labelled as the "Tertiary Sector" and a mark placed at 20 on the line extending diagonally upwards from this axis. Where the three points intersect is where the cross is placed. Data from other countries may then be plotted on the graph for comparison.
The main advantages of these graphs are the fact that they can display a large amount of data on one graph, and clusters of poitns clearly highlight points of similar value meaning patterns in the data are clear; in fact it is only when a large amount of data is plotted that trends become visible on the graph. They are most likely to be used in conjuction with, or instead of, pie charts, because they show percentages and proportions. However these graphs are hard to construct and interpret, and only a very limited amount of data can be plotted using this type of graph.