Discrete versus continuous (blue versus green fields – otherwise known as pills)
The customary rule of thumb is that measures are green, or continuous, and dimensions are blue, or discrete. In most cases, this is accurate, but measures and dimensions can be both discrete and continuous.
Tableau considers continuous fields as fields with an infinite range that can create an axis for a visualization. On the other hand, discrete fields are finite and are used to build headers for a visualization.
The most common data types in dimensions that see a continuous value are dates. To test which fields can be modified to discrete or continuous, you simply need to right-click the field to see whether it can be converted from discrete to continuous or continuous to discrete. Dimensions that do not permit changes from discrete to continuous or vice versa will not show this option. Please see Figure 4.4:
Figure 4.4: Order Date is a discrete dimension but...
