Setting the Map Type

The second tab of the Map Expert is the Type tab. It lets you choose between five different ways of plotting data. The five types of maps to choose from are Ranged, Dot Density, Graduated, Pie Chart, and Bar Chart. Each one has a different purpose and you have to set certain properties to control how it looks. The options are shown in Figure 14-4.

Figure 14-4. Type tab of the Map Expert.

The available map types are shown in two groups. When looking at the Map Expert dialog box, you’ll either be able to choose from the first three or the last two map types, but not all of them at the same time. This is because each has different requirements for the type of data it can display.

The first three types are Ranged, Dot Density, and Graduated. They simply plot a single value on each point on the map. Thus, they only need data for the map location and a summary value.

The second two types are Pie Chart and Bar Chart. They are a little more complex because they map multiple values on each point. They need three different data fields to work properly. In addition to needing the geographic area and the value to plot, they need a third data field that the value can be plotted against. This data field could be a group of products that will be compared against each other in a pie chart, or a date field to be used as the X-axis in a bar chart.

The way to determine which group of map types will be available is by looking at the On Change Of field. If the On Change Of field is the same data field for Geographic Area, then you can only use the types Ranged, Dot Density, and Graduated. However, if the Geographic Area field is different from the On Change Of field, then there is a third data field to work with and you will be able to use the Pie Chart or Bar Chart map types.