A National Park Service study confirms that 3D maps benefit most novice users.
Three-dimensional maps help users more accurately identify their position on the landscape compared to their 2D counterparts, and are preferred by younger users, women, and non-native English speakers, according to a recent study by the National Park Service.
And while the study concluded that older respondents, men, and native English speakers generally prefer 2D maps, it also showed that 3D features attract more users overall to actually read trailhead maps and keep their attention for longer than 2D maps.
“The conventional wisdom among the mapmaking community was that 3D maps are easier to read for novice map readers, which comprise the majority of the population visiting our national parks,” says Tom Patterson, senior cartographer with the National Park Service’s Harpers Ferry Center, the park system’s interpretive design center. But Patterson found scant literature on the topic so, during his presentation at an international map conference in 2004, he outlined a methodology for comparing the effectiveness of the two types of maps, and sought researchers to undertake the study in a U.S. national park setting.
In September 2006 the users study was conducted at Utah’s Zion National Park. The results, says Patterson, both confirmed and challenged his assumptions about 3D maps.
2D vs. 3D maps
NPS currently uses both 2D and 3D maps. Most existing maps, including NPS trailhead maps and U.S. Geological Service topographical maps, are two-dimensional, depicting the landscape from a point directly overhead. 2D maps accurately portray the spatial relationships (x and y dimensions) of a landscape, but are ill suited for depicting the height of terrain (z dimension).
Three-dimensional maps, sometimes called bird’s-eye views or panoramas, depict the landscape from an oblique angle and in perspective. They contain faux three-dimensionality and perspective that portrays distant (background) areas with diminished scale. The landscapes shown on 3D maps appear similar to the views people observe from high places, such as mountain peaks.
Many cartographers believe that inexperienced users more easily understand 3D maps because they present the landscape in a realistic manner and mimic what people see while on a trail. 3D maps also provide the option for customizable viewing direction and position, make elevation changes easier to understand, and are more visually appealing. They can also be overlaid with abstract or photo-realistic information, including detailed building footprints.
But 3D maps can cost 200% to 400% more to produce than 2D maps, says Patterson. “Because of all the detail you can add to a 3D map to make it more visually appealing, all the layers of data have to be in absolutely perfect register, or the final piece will be sloppy. Cartographers have to spend a lot more time finessing the data so everything aligns perfectly.”
The study sought to answer several questions about the effectiveness of 3D vs. 2D maps:
- Which communicates geographic information faster and more effectively?
- Which imprints itself better as a “mental map” in the minds of park visitors?
- Which attracts more visitors to read trailhead exhibits, holds their attention, and motivates them to go hiking?
- Which do national park visitors prefer?
The study was undertaken at Zion National Park during a three-week period in September 2006. It was conducted by David Schobesberger, a masters-degree student in cartography at the University of Vienna, Austria, in collaboration with Patterson and the Zion National Park staff.
User data were collected on two trails, one popular with novice hikers and the other favored by experienced hikers. For both trails, inkjet prints of 2D and 3D maps were mounted to existing trailhead signs on alternating days. Except for the 2D or 3D appearance and lack of a bar scale on 3D maps (their scale is not consistent), the maps contained the same information, orientation, and design qualities.
Two types of data collection were used: passive monitoring of visitors as they read trailhead exhibits, and a questionnaire administered to hikers while on the trail. Schobesberger collected 340 observations of hikers at trailheads and helped users complete 185 questionnaires.
The four-part questionnaire gathered data on respondent characteristics (age, gender, hiking experience, etc.); interaction with the trailhead map (did the respondent look at the map, and for how long?); questions about map content; and a map positioning task and map design preference. For the final part of the questionnaire, hikers were asked to mark their current location on a map to determine how well they could read it, and were asked which type of map they preferred. The average response rate for the questionnaire was 90 percent.
Data from the observations and questionnaires helped NPS determine how hikers rated the two types of maps, how well they were able to orient themselves using them, which maps they preferred, how well the two maps communicated cartographic information, and which maps attracted their eye and kept them looking longer.
Hikers were asked to rate the trailhead maps on design, readability, and the impression they gave of the landscape. Hikers on the easier trail rated the 2D map higher, while hikers on the more challenging trail ranked the 3D map higher.
In general, hikers accurately identified their positions with the 3D maps more than with the 2D maps. “Data from both trails suggested that a broad spectrum of hikers (especially females and hikers over 60 years old) do better orienting themselves on 3D maps,” says Schobesberger.
3D maps were clearly preferred by the 26-40 age group, but 2D maps were preferred slightly more often in the 15-25, 41-60, and over-60 age groups. Females, left-handed people, and non-native English speakers preferred 3D maps.
Significantly, hikers who actually looked at the trailhead map before setting off on their hike preferred 3D maps. According to Patterson, “It makes practical sense to design trailhead maps for the hikers who take the time to read them, not for those who don’t—think of this as cartographic triage. We need to tailor maps to the preferences of our map-reading audience.”
Hikers were asked a series of questions to determine how well the maps communicated the information mapmakers intended. Both map types were shown to be equally well suited for communicating spatial information. 3D maps showed a slight advantage in their ability to communicate distances and a general overview of topography, while 2D maps are slightly better for communicating place names.
Map attraction and viewing time
3D maps were shown to be better at attracting and holding the attention of users (50% looked at the 3D maps, while only 44% looked at the 2D maps). This finding highlighted a discouraging observation, however. “Even in the best-case scenario, 50 percent of hikers did not read the maps at all,” Schobesberger notes. Hikers who did use the maps viewed the 3D maps for an average of 44.1 seconds, 3.1 seconds longer than the 2D maps. “The longer the user read the map, the higher he or she rated it for design.”
Patterson says the study both affirmed and challenged his thinking about 3D maps. “It basically showed that not all novice hikers necessarily benefit from 3D maps. We discovered that older hikers, men, and native English speakers for some reason did not benefit as much from 3D maps as the other groups did. That was surprising.”
Another finding that surprised Patterson was that 3D maps proved more effective in helping users identify their location. “That flies in the face of convention because 2D maps are completely spatial, with just X and Y coordinates. We thought location tasks would be more efficient with 2D maps. My theory is that, despite 3D maps having front-to-back scale variation, people could look at the various landforms on the map and identify things they recognized.”
Indications that younger users prefer 3D maps leads Patterson to believe that more 3D maps are in order to connect with the next generation of park visitors. “I expect that kids growing up today immersed in virtual computer environments will more easily relate to 3D maps than we do—these maps will have become the norm.”
And he notes that the study’s implications reach beyond trailside park signs to urban wayfinding systems. Because 3D maps are so effective at showing large-scale scenes—including transportation infrastructure and architectural detail of buildings—3D maps are ideal for helping users navigate through urban spaces.
“We do a lot of urban cultural sites for the park system and we’re including more 3D mapping in these settings,” notes Patterson. “When you get to a scale where you can see buildings and trees and come into a more human frame of reference, that’s where 3D mapping really shines.”
The National Park Service study by David Schobesberger is available at www.nps.gov/hfc/carto/zion_map_study.pdf.
--By Pat Matson Knapp, segdDESIGN No. 23, 2009