Visual hierarchy

From Wiki.GIS.com

Visual hierarchy is the order in which the human eye perceives what it sees. It is used in cartography to help the map designer create a product where the viewer will process the information presented in order from the most important to the least important. This can be achieved by manipulating different pieces of a map such as its color contrast, symbology, texture, shape, position, scale, orientation and size.^[1]

Visual hierarchy is related to Gestalt psychological theory, which proposes that the brain has inherent organizing characteristics. The theory suggests the we subconsciously notice certain objects before others. It states that the human mind tends to "structure individual elements, shapes or forms into a coherent, organized whole."^[2] When presented with a picture, map, or other visual stimuli, the brain will take individual elements of the scene and organize them into a whole. The elements that most sharply contrast from the brain’s perception of the whole are most noticed by the viewer. The greater the disconnect of an object from its surroundings (the whole), the more the brain highlights it as important to take note of. For example, the fluorescent color of tennis balls contrast with their surroundings, making it easier for a tennis player to focus on during high-speed play.^[3] An example from cartography would be that a title in large font at the top of the map will be higher in the visual hierarchy than a smaller subtitle at the bottom of the map.^[4][5][6]

By focusing on visual hierarchy while designing a map, a cartographer can ensure two main goals are met : first, that the main purpose for creating the map will be understood by those viewing it, and second, that the viewers will be persuaded to accept the message the map is trying to convey.

When an object is disconnected from the ‘whole’ the human eye notices the disassociated object before it notices the ‘whole’. An example in cartography is represented in the following map.

The thicker blue and red roads and road signs are more prominent on this map to the human eye than the lighter background. The freeways and highways are the disassociated objects while the rest of the map would be considered the ‘whole’.

[edit] Negative Space

Also known as “white space,” negative space is the empty space on a map that is available for placing map elements. The Contrast created by the negative space placed against the space occupied by map elements helps establish a visual hierarchy for the features that convey the message of the map. Because of its plain nature, negative space helps keep maps simple and readable. Maps that don’t use negative space wisely become cluttered and may therefore fail to convey their desired message. See also "Map Symbology" in Cartography.^[7]

[edit] References