Before you Map: Audience, Medium, and Purpose

Before you Map: Audience, Medium, and Purpose 

There is no inherently good map—only a map that is well-designed and properly suited to its audience, medium, and purpose. Before creating a map, you should ask yourself (and if possible, your clients) several questions (Brewer 2015).

Audience—who is going to use this map?

• Will your map readers be novices or experts? Do they have advanced knowledge related to the data you intend to map? You would create, for example, a different map of crime hotspots for criminologists than for the public.
• Are your intended map readers knowledgeable about the area to be mapped? Those unfamiliar with a location might need more detail to understand its geographic context.
• How much time will a typical reader spend with your map? Some audiences will be happy to explore and analyze your map, while others may hope to understand the message of your map at a glance.
• Is your map accessible? Consider how colorblindness or other visual impairments might affect your readers’ interpretation of your map.

Figure 1.4.1 Two similar maps of city water utilities appropriate for different audiences. The map on the left includes additional symbols that are useful only to experts. The map on the right would be more suitable for a busy audience, or non-experts.

Credit: BeavertonOregon.gov

Medium—how will this map be displayed? 

• Maps are viewed in a vast number of formats—in desktop browsers, on mobile phone screens, in brightly-lit rooms on large-screen projectors, as well as printed in magazines, brochures, newspapers, posters, etc.
• In addition to the broad media category (e.g., mobile phone browser vs. poster), predict the specifics of your map's final viewing format as much as possible—details such as the map’s size on a webpage or a reader’s viewing distance from a poster can make a big difference in both a map's utility and aesthetics.
• If your map will be viewed in multiple media formats, you will likely have to create multiple versions of your map, each optimized for its respective display medium.

Figure 1.4.2 Three maps of the same data suited to different display mediums. (Left) This map is detailed and suitable for high-quality display media. (Middle) This map is simplified for lower-quality displays or when viewed from farther away. (Right) This map—rather than just being a black-and-white copy of another map—has been optimized for greyscale reproduction.

Credit: Cary Anderson, Penn State University; boundary data source US Census, thematic data invented.

Purpose—what is the intended function of your map?

• Maps are used for many purposes (e.g., for navigation, for understanding spatial trends in data, for site selection, for communicating the results of a research project, etc.) Different purposes necessitate different maps.
• When making design decisions, consider how they will influence the success of your users in completing their expected map-use tasks. Maps for driving navigation, for example, are generally more useful when detailed terrain data is excluded, creating a simpler interface. In a hiking map, however, such information is essential.
• Considering in what scenarios a map will be used is also important—users of maps for emergency response, for example, will likely be stressed and working under inflexible time constraints.

Figure 1.4.3 Two maps of trains designed for different purposes. The top map is specifically designed to be used in a train control center. The bottom map is designed for transit passengers - it is much simpler and only describes what passengers need to know. Note that while these maps do not depict the same location, they demonstrate how different symbol designs are more or less appropriate for different map use tasks.

Credit: Australian Government Transport Safety Bureau; Seattle.gov.

In this course and beyond, you will make many different kinds of maps. Some will be advertisements, some will be scientific documents - some may be just for fun. No matter the mapping project or process you use, pausing to reflect upon the who, what, and why of your map will always lead to better results. 

Figure 1.4.4 Considering the who, what, and why of a mapping project.

Credit: Cary Anderson, Penn State University.