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Scale, Map Elements, Map Layouts, Type, Thematic Maps,
Data Classification Methods, Color Choices, and
Digital Map Distribution Formats
cartography the art and science of creating and designing maps
One thing that makes spatial data unique is that it can be mapped. Once you’ve used GIS to create the boundaries of a Civil War battlefield and analyzed its proximity to new housing and commercial developments, the next step is to make a map of the results of your work. However, making a good map with GIS involves more than taking the final product of the analysis, throwing on a title and legend, clicking on “print,” and then calling it a day. There are numerous design elements and considerations that should be taken into account when you’re laying out a map. In fact, there’s a whole art and science of mapmaking (called cartography), involving things like color selection, the positioning of items on the map, or what kind of message the final map product is intended to convey to the reader.
map a representation of geographic data
A map is a representation of spatial data that is designed to convey information to its reader. Making digital maps with GIS offers a wide variety of options for creating an end-product, but there are a few considerations to take into account before you start the mapping process. For example, say there’s a park nearby—a municipal wooded area that’s used by the local populace for walking trails, biking, picnicking, or walking dogs. The only map of note is an old hand-drawn one you can pick up at a kiosk at the park entrance, and the local government wants to update it. As you’re the local geospatial technology expert, they come to you to do the job. Before you break out your GIS tools, there are some basic questions to ask that are going to define the map you design.
visual hierarchy how features are displayed on a map to emphasize their level of prominence
First, what’s the purpose of the map, and who will be using it? If the park map you’ve been asked to design is intended for the park’s visitors to use, then some of the important features the map should contain are locations of park entrances, parking, comfort stations, and designated picnic areas. It should be at an appropriate scale, the trails should be accurately mapped, and trailhead locations and points of interest throughout the park should be highlighted. If the map is to be used for zoning purposes, things like exact boundaries, road systems, and parcel information will likely be some of the most important factors. This is part of the visual hierarchy of the map, which determines those elements of the map that are most important (and thus, most prominently displayed) and what information is less important (and therefore not so visually conspicuous).
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Why is Map Design Important?
Why is a map’s appearance so important? After all, you could argue that a poorly put together map of New Zealand is still (at the end of the day) a map of New Zealand. However, a well-designed map is going to be more useful than a poorly designed one—but why? Why are things like the choice of colors, lettering, and placement of items on the map critical to the usefulness of a map? Consider what kind of effect a poorly designed map might have, and what sort of impact bad design could make on the usefulness of, say, a map of a local county fair, a real estate map of a new subdivision, a promotional map showing the location of a small business, or a map of a proposed new urban development readied for promotional purposes. How can the design of a map influence the way the map’s information is perceived by its reader?
Second, is the information on the map being effectively conveyed to the map reader? For instance, if you’re designing a trail map, should all trails be named or marked, or will that cause too much congestion and clutter on the map? Will the colors and symbols be easily understood by the kind of novice map readers who just want to find their way around the park? The trail map will likely not need an inset map of the surrounding area to put the park into a larger context, nor should the map reader be left guessing the meanings of the symbols used on the map.
Third, is the map well designed and laid out properly as a representation of the park? A good map should be well balanced with regard to the placement of the various map elements, for best ease of use by the map reader. This chapter will examine several of these cartographic design and data display functions, and by the time we reach the lab, you’ll be designing a professional-looking map of your own, using GIS.