Yes, wok sales are increasing and our canny artist used a vertical bar chart to emphasize this. Just the ticket for a presentation to a stock analyst studying the prospects of the Amalgamated Wok Corporation. Notice that numbers are easier to take in than those on a line chart.
“You might have a vertical bar for 1979 wok sales slightly overlapping with one for 1979 widget sales and continue these twin bars for the next five years.
“Use overlapping bar charts when you’re showing trends for a number of different products or categories.”
Wow! Look at the hefty wok sales in November and December. Someone offer rebates? Actually you’d be better off using a pie chart instead to show the percentages of semi-annual sales from different regions. Regions, not the 50 states. You can only slice a pie so thin.
Yet another tool, the pie chart, just like a pie, with slices, nicely shows relations of complete parts.
Use the pie chart to show the percentage of sales that came from four or five regions.
On the other hand, suppose you have many, many small components in your pie—say, you’re interested in the percentages of domestic sales in each of the fifty states. Then a map with percentages on it might be better.
I’ll stop here—this is a computer book, not a graphics guide. For more detailed information, Herrman recommends Designer’s Guide to Creating Charts and Diagrams by Nigel Holmes (from Watson-Guptill, New York).