Pyramid Charts in Geography
What is a pyramid chart?
A pryramid chart is often refered to as a population pyramid as they are typically used to present age-sex data for an area. They look lik two bar charts on their sides. They are usually presented as five or ten year age groups with males on one side and female on the other. Horzontal bars are drawn to present the number or proportion of males and females in each age group.
When is using a pyramid chart appropriate?
A pyramid chart is appropriate for presenting population data to show the age and gender breakdown of a country’s population. Pyramid charts can be used when two sets of coninuous data is available, for exmaple a pedestrian count for a continuous timescale showing people moving in two directions.
Creating a pyramid chart
There are two ways of presenting population pyramids. The first is with the y-axis being plotted to the left (see below) and the data expressed as percentages.
Population Pyramid for the UK
The second is with the y-axis being plotted between the bars (as shown below), and in this case the raw population data is shown.
A population pyramid for the UK in 2016
Step 1 – here
Draw the horizontal and vertical axis for your pyramid chart. The same scale should be either side of the horizontal (x) axis.
Step 2 – here
Draw each of the bars to the correct value.
Step 3 – here
The bars should be coloured the same because it is continuous data.
Reading a pyramid chart
The shape of a pyramid chart provides an overview of the data. In the case of population pyramids, if they have a wide base, it indicates a high birth rate. If the pyramid has a quickly narrowing top, death rates are high. You can extract data from individual bars by using the x-axis to read the value.
Create your own pyramid chart