GIS Tech News #15
20 Mar, 2006 By: Kenneth WongGreen maps come together easily using GIS data and the right software tools
The Art of Ecological Cartography
Green maps come together easily using GIS data
and the right software tools
If you’ve just relocated to Brooklyn and want to know how to get around, you can pick up a local transit map from any Rand McNally store. If you’re an MIT freshman trying to navigate a maze of classrooms, auditoriums and dormitories, you can get a campus map from the university bookstore. But what if you’re an eco-conscious citizen in search of a map more suited to your lifestyle? What if you want to locate all the bike lanes, repair shops, bike racks and seasonal green markets in Brooklyn? What if you want to know the location of recycling bins on your campus?
A decade ago, faced with this type of nontraditional cartographic desire, you would have had to consult the phonebook, explore the locale on your own and annotate a commercial map with a marking pen. But today, with powerful search engines and affordable mapmaking applications at your disposal, you can make a digital map and share it with the community at large. That’s what the organizers of Green Map System, part of a global eco-cultural movement, encourage people to do.
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A variety of green map samples of New York City; Hamilton, New Zealand; Hiroshima, Japan; London, United Kingdom; and Dublin, Ireland. |
Drop Your Paper Cups Here
Jerrad Pierce, now an experienced green mapmaker, recalls his first endeavor: “I’d heard from a number of [MIT] students that they didn’t recycle because there weren’t any recycling bins. I knew this to be false. At the same time, I came across an ad [from Green Map System] in the back of The Ecologist magazine for green maps, so I decided to create a map of the recycling bins on campus.”
In 2005, as part of his MIT study, Pierce submitted his undergraduate thesis, “Improving the Cartographic Quality and Design of Greenmaps,” to the Department of Urban Studies and Planning. Green mapmakers often employ professional graphics programs, such as Adobe Illustrator or Photoshop, but, according to Pierce, those are not necessarily the best tools for cartographic purposes. In his thesis, he argues that GIS software is “specifically designed for handling spatial information like that which constitutes green maps. A GIS facilitates data sharing, organization, analysis and rapid prototyping. Many green maps are made without the benefit of a modern GIS.”
Pierce uses ArcMap, a cartographic application from ESRI’s ArcGIS Desktop family. He has since expanded his green map’s coverage from the campus area to Cambridge and its environs. He also maintains and updates a style guide for using Green Map Icons, the official symbology of Green Map System.
In Search of Green DataPierce acquires the geographic datasets he needs from a variety of public sources, including MassGIS, a free GIS site from the Commonwealth of Massachusetts, and the Harvard Geospatial Library. Some eco-centric cartographic information, such as coordinates of power plants and water sources, readily exists in geospatial format compatible with ArcMap. On the other hand, some highly specialized data, such as addresses of vegetarian restaurants within the area, is not easily available. If such data does exist, it often takes the form of textual information, so collecting it can require quite a bit of creativity.
“I found [the locations of] vegetarian restaurants through the MIT vegetarian club,” Pierce says, “because they already have a vested interest in it and they’ve scouted out most of the places. Often finding information involves digging around and asking nicely.”
Sometimes he doesn’t even have to ask. When Zipcar, a car-sharing program that operates in numerous major metropolitan areas, learned about Pierce’s project from a previously published article, the company contacted him with information about ZipCar pickup locations, in geospatial format ready for import.
Blending Geospatial Mediums“I came across four or five different sources for [the locations of] open spaces,” says Pierce. “The City of Cambridge has one, ESRI has one, and [the data is] available at a couple of other places at various scales. Different layers have different features, and some are missing features. As a good mapmaker, when I’m blending them, I want to keep track of where they are from and record the source of each.”
Here, he finds himself stretching the limits of the metadata tools in ArcMap and ArcCatalog (a dataset manager application for ArcGIS). “They’re somewhere between being too structured and too freeform,” he observes. “There are several tabs or panels, but for the most part, you enter freeform text, so you have to figure out what you want to record instead of selecting fields from pull-down menus.”
Ideal Icon Placement“In green maps, most of the symbols are point symbols, so for high-density areas, there are a lot of point symbols. In my case, I can afford only a two-color printing process, so I can’t really allow too much overlap.”
Pierce is considering using Maplex for GIS, an automated label-placement program, to help prevent symbol collisions. For the most part, the labeling engine does save time, but he’s hoping for even more flexibility and automation.
The Maplex labeling method allows a user to assign priority numbers to eight zones around a point to indicate preferences for label placement. Based on this input, the program picks the best placement option to avoid collisions with nearby labels. “In my case,” Pierce points outs, “I don’t care which direction the labels go, so long as they are on the feature or close to the feature.” To him, all these options are equally acceptable. “What I’d like to be able to do is to enter [priority] 1 to the center, and then enter 9 for the surrounding edges,” Pierce says.
ESRI points out the best workaround to Pierce’s problem is to choose Centered as the preferred placement, and then to toggle on the option for May Shift Label on Fixed Position, which allows Pierce to accomplish what he wants. With this option turned on, if Maplex cannot place the label at the center of an object because it conflicts with nearby labels, then it automatically tries to position the label around the center.
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Green mapmaker Jerrad Pierce doesn’t necessarily want to have to specify in which corners of a grid a label should be placed, so long as it’s centered or close to the center and doesn’t conflict with nearby labels. To accomplish this, ESRI suggests Pierce let Maplex automate the process by using the May Shift Label on Fixed Position option. |
Make Your Own Green Map
Green mapmakers and their stories are as diverse as imaginable. In Kyoto, Japan, the Tennen Design Forum gave birth to the Kyoto Green Map in 1997, during the United Nations Climate Change Conference. It chose light purple as the base tone, to match the Japanese expression Sanshi-Suimei (purple mountain, lucid water). For an architect and GIS aficionado in Pune, India, inspiration for a green map of his sunny city came from a verse from the ancient classic Bhagavad Gita. Not all green mapmakers are professionals. Some are children and young adults publishing maps in bright crayon colors.
To produce something with professional finish, you might not even need a costly GIS package. Pierce suggests the resources listed at FreeGIS.org as well as free mapmaking applications such as MapWindow.
For more on mapmaking, read James Sipes’ GIS column “Spatial Technologies: The Art of Cartography” in Cadalyst’s February 2006 issue.ABOUT THE AUTHOR
Kenneth Wong is a former editor of Cadence magazine. He explores innovative use of technology and its implications in GIS Tech Trends and in Cadalyst magazine’s PLM Strategies column. Reach him at kennethwongsf@earthlink.net.
UPCOMING GIS EVENTS
Cadalyst'scomplete list of upcoming events is always available on our Web site. Cadalyst's sister publication, Geospatial Solutions, also offers a full calendar of GIS-related events.
GITA Annual Conference 29
April 23–26, 2006
Tampa Convention Center, Tampa, Florida
GITA (Geospatial Information & Technology Association) will offer an expanded series of track topics at its annual conference, as well as nine preconference knowledge immersion seminars, user forums, panel discussions, networking socials, a job fair, a poster session and a 100,000-square-foot product and services exhibition.
Homeland Defense Journal Training Conference
May 4, 2006
Arlington, Virginia
With the theme “Achieving Actionable Situational Awareness: Geo-Spatial Solutions – The Next Generation,” this conference is directed at government and industry executives and decision-makers.
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