Bar charts for quantities
Time series are often displayed in a time series plot — a kind of scatterplot with time on the horizontal axis and the successive crosses joined by lines.
When the values being displayed are quantities of something (values that must be positive), an alternative is to represent them with a bar at each time point. This is a kind of bar chart in which the time points can be considered to be categories.
New Zealand wine production
The bar chart below shows how the area in New Zealand used for vinyards changed between 1962 and 2001. (Area is a quantity — doubling the area is a meaningful concept.)
Select Production from the pop-up menu to see how wine production changed over this period. In contrast to the steady increase in vinyard area, wine production has fluctuated markedly since 1980 and has levelled off.
Another interesting measurement for producers is the ratio of production to area — the production per acre. Select Production per hectare from the pop-up menu to see how this has changed. Production per hectare has steadily dropped since 1970.
Possible explanations are...
Further information is required to assess these explanations and fully understand this pattern.
Select the option Time Series from the pop-up menu on the left. Since the data were recorded each year, time series plots can also be used to display them.