Visual Hierarchy in Map Design

Visual hierarchy is the intellectual plan for the map and the subsequent graphic solution. On a map, visual hierarchy is used to highlight the importance of features relative to each other. For the most part, this is accomplished by creating a sense of depth on map. It is closely related to the concept of figure/ground.

One important aspect of visual hierarchy is the gestalt theory of figure-ground that has been well-illustrated:

See if you can get each of these illustrations to switch between foreground and background. The ambiguity highlights the problem of visual hierarchy. It also highlights how our visual system attempts to impose order on the visual display.

Gestalt psychology (German: Gestalt "shape, form") is a theory of the mind of the Berlin School of experimental psychology (early 20th century). Gestalt psychology tries to understand the laws of our ability to acquire and maintain meaningful perceptions in an apparently chaotic world. The central principle of gestalt psychology is that the mind forms a global whole with self-organizing tendencies [Wikipedia: Gestalt psychology]. Gestalt has major implications for graphic design.

The map below illustrates the figure/ground problem in the context of land and water. It is difficult to determine which is which.


Let's introduce some terms to describe what we're talking about:

Visual heirarchy is a part of the grammar of communicating with maps.


What is the visual heirarchy of these graphic elements?

What is

The mapping of an urban area is even more problematic in the sense that multiple levels of hierarchy must be communicated such as in this map of Berlin:

Notice the multiple levels that are communicated. One of the major differences between maps of Europe and North America is that our maps tend to rely more on lines (rather than shapes) and do not implement visual hierarchy as well:

Notice the Google Map has a higher level of visual hierarchy. White lines have been used against a grey background to create the individual blocks. Both maps of San Francisco are "flat" in comparison to the map of Berlin.

The following illustration shows three versions of the same street map:


Summary on figure-ground from ESRI

Four examples from ESRI - mapping a closed form (A), using a whitewash (B), adding a drop shadow (C), and using feathering (D).

One, somewhat cheating, way of creating visual depth is the use of the drop shadow effect. This can be created by placing a slightly offset filled polygon behind the foreground map. The offset in the first map is to the southwest. The offset is usually done to the southeast.

drop shadowusa drop shadow

These maps use hill-shading to create a sense of depth. The first map of the Swiss Alps was done by hand using an airbrush. The shadings in the second map were calculated by computer.

Imhof map National Park