What does "faceting" mean in a geo/map context?

Question

I saw some folks talking about "faceting" in relation to a map data display, what does this mean in general terms? Examples?

Answer 1

One concept of 'faceting' is to display data in separated maps (known as panels), so to emphasize groups or subgroups of data.

For example, each panel can represent a timestamp (commonly used to represent historical climate data). Here is one example from New Zealand's National Institute of Water and Atmospheric Research.

First time I came across 'faceting' was with R package ggplot2. For instance, see Overlaying a polyshape to faceted maps in R with ggplot? (more examples can be found in Google, link).

Moreover, as pointed out by Steven Kay, another term for 'faceting' is small multiple maps. Indeed, a quick search in Google also returned many true positives for it.