Know your audience
When producing maps for the public, such as a bus system map or a specific route map, it is beneficial to moderately distort the map rather than displaying exact geographic reality. People understand maps with moderate levels of geographic distortion better than highly detailed maps because the distortion minimizes the number of things they have to absorb, so long as key geographic features are retained and labelled.
When producing maps for an audience of planners or technical experts, distortion is not likely to be needed.
Distortion for the public
Accuracy for a technical audience
Visually prioritize transit
Transit lines should be bold, bright, and sit at the top of the visual hierarchy. People appreciate background detail but they want to see transit lines above all else.
Bold, bright transit lines
Provide reasonable background detail
Include some level of geographic background detail such as bodies of water, green spaces, and major roads. People benefit from these contextual elements but are often irritated by additional contextual elements such as minor roads, building footprints, and activity centers.
Label all major background features. People do not like to guess as to what they're viewing.
Include major roads and natural features
Minor roads, buildings, and major activity centers are often distracting
Balancing Detail & Clarity
Getting the right balance of visual content is key
A standard bus map should include bus lines, major streets, and some natural features. Less or more visual information than this detracts from the overall clarity of the map.
Too little contextual visual information. People don't find this clear.
Better, but if there are a few key geographic or natural features that can be added, people benefit from seeing them.
Include major streets and natural features to provide the best visual balance between background detail and overall clarity.
Additional visual elements, such as buildings and minor streets, start to diminish the overall clarity and coherence of the map.
Making the best use of specific design elements
Prioritize background features as follows:
water features & green spaces
directional arrows on bus lines
Use sans serif fonts to the greatest extent possible
The vast majority of people prefer sans serif fonts to serif fonts in maps.
Use Gotham X Narrow font for dominant map labels
Among fonts commonly used in Nelson\Nygaard map labels, Gotham X Narrow appeals to the widest audience. Consider PW Centra as an alternative.
Use Gotham X Narrow or Bahnschrift fonts for secondary map labels
Among fonts commonly used in Nelson\Nygaard map labels, these two fonts appeal to the widest audience.
Sans Serif > Serif
Use bright colors for bus lines
People are most attracted to bright, vibrant colors that make transit or bus lines stand out on a map. Muted, pastel and dark colors can be viable alternatives, but monochromatic lines should be avoided.
Use a white background
People are most attracted to white backgrounds. Consider light grey as an alternative, but avoid dark colors.
Use a light blue for water
People are most attracted to light blue as a water color. Consider a vibrant bright or darker blue as an alternative but avoid grey or white.
Make lines thick
Thicker line widths are more popular than thinner lines.
Offset lines slightly, but not excessively
When offsetting bus lines along segments where routes overlap, it is best to offset lines slightly such that there is a narrow visible gap between lines. If space on a map is limited, consider offsetting the lines with no visible gap between lines as an alternative. Avoid very wide offsets, which make it more difficult to understand that routes operate parallel to one another.
Include anything that isn't directly labelled on the map in a legend
Legends should show only primary map elements; ideally secondary map elements such as roads or bodies of water should be labelled on the map. However, when such labelling is not possible unlabelled map elements should be explained in a legend to minimize uncertainty for the viewer.
Show distance and travel time on a scale bar
A plurality of people like to see scale bars that show not only distance but also travel time. Show travel time of whichever mode of travel makes the most sense at a given scale or given a map's subject matter. On most bus maps, walk times should be shown because bus riders get to and from bus stops on foot. At larger extents with larger scales, it may be appropriate to show drive, bus travel, or bike travel times.
Map rotations are acceptable
Most people will accept and understand the rotation of a map away from true north if this aligns with local understandings of geographic orientation.