When is a divergent color ramp most appropriately used?

A divergent color ramp is most appropriately used when there is a need to highlight values above and below a central median. This type of color ramp typically employs two contrasting colors to represent deviations from a mid-range value, allowing for a clear visual representation of how data points cluster around that center.

Using a divergent color ramp helps in identifying not just the extremes in the data set but also the transition around the median point. For example, this is useful in contexts like temperature anomalies where one color might denote temperatures that are above average while another represents below-average temperatures.

Other options refer to scenarios better suited for different types of color ramps. Light intensity levels would typically be represented with sequential color ramps, where a single hue lightens or darkens to show intensity. A single continuous data set would also use a sequential ramp to effectively convey gradations in a single variable. Qualitative data, which involves categorical distinctions without inherent ordering, requires a distinct color palette rather than a ramp, as each category should be easily discernible without suggesting a numeric progression.