GIS

Spatial Technologies-Urban Planning Builds on GIS Data

1 Sep, 2005 By: James L. Sipes

Power to the people


According to the U.S. census bureau, more than five billion people will live in urban areas by the year 2025. Are we prepared to handle all of these people? Not a chance. Urban design and planning issues are becoming more complex, and traditional planning and design techniques are inadequate for addressing many urban changes. In the old days, planners may have had to wait years to see whether their policies and decisions were successful. As a result, most municipalities were in a reactive mode, trying to solve the most immediate decisions at hand and too often ignoring long-term planning concerns.

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Local governments must provide urban planning services to their constituents. Failure to do so leads to chaos and confusion. Roads would have no rhyme or reason. Natural resources would be totally overwhelmed by the built environment. Development would be out of control, roads would fall apart, trash would pile up on the streets and we would have no place to play or recreate.

At the same time that urban planning issues are becoming more complex, citizens are no longer willing to let planning professionals make all of the decisions about their community. The days of planning in a black box are gone, and concerned citizens want to know not only what decisions are being made, but also how and why they are being made. Although it may take longer to make design and planning decisions, the likelihood of these decisions being implemented is much greater because of public involvement. As a result, GIS has become an essential tool in urban design and planning. The ability to create, modify, and analyze data is a major part of all decisions about urban communities. Thematic layers that show information such as land use, transportation corridors, census data, employment statistics and other types of information can be combined to study how decisions may affect a community (figure 1).

Figure 1. GIS can combine data from multiple sources, as shown in this planning model of a section of Atlanta.
Figure 1. GIS can combine data from multiple sources, as shown in this planning model of a section of Atlanta.

Urban Design and Planning

The urban landscape is in a constant state of flux. The next time you drive through a major city, pay attention to all of the construction. Urban designers and planners are the ones making decisions about how cities grow and develop. Urban planners typically determine policies and procedures, and urban designers work within this structure to give physical form to our cities.

Some of the activities that may occur during this process include transportation planning, emergency service planning, streetscape designs, routing studies, pedestrian circulation analysis, zoning analysis, land-use planning, view analysis, air- and light-pollution studies, urban vegetation management, demographic studies, historic preservation, security and wind and shadow analysis.

Urban designers typically start by conducting a thorough inventory and analysis to find out more about a site and its environment. The program for a project and subsequent design decisions are based in large part on this analysis. Urban designers need to have a thorough understanding of a site to ensure a successful project. The more detailed, complete and comprehensive the data, the better the analysis will be.

Most of the information needed to make decisions about urban communities at a broad level currently exists, but it needs to be analyzed and organized in a meaningful way. Integrated regional land-use databases are becoming more common, and dozens of sources provide most geospatial data needed for an urban planning project. Aerial and satellite images give urban planners the ability to view geospatial information and identify features on the ground, and this helps them make educated decisions.

Figure 2. 3D models of urban areas (Tampa, Florida, is shown here) are readily available from many sources.
Figure 2. 3D models of urban areas (Tampa, Florida, is shown here) are readily available from many sources.

3D models are effective for showing details of major urban projects, and 3D GIS data can be generated with technologies such as LIDAR and better CAD/GIS integration. Existing 3D models for most major cities are available from vendors such as CyberCity and GeoSim Cities, eliminating the need to create everything from scratch (figure 2).

One problem, though, is a lack of detailed data needed for site design. The GIS data that is available is too coarse to be used for anything other than large planning projects. In particular, there's a real lack in socio-economic data.

"If there is not sufficient GIS data available, we have to either go out with GPS units or decide that the data is not important," says Pat Peters, senior associate with EDAW, a design and planning firm with offices all over the world. It comes down to whether designers are able to sell a client on the value of building a GIS data layer for a specific project. "Too often we wind up generating drawings and maps by hand instead of building the GIS layer. Unfortunately this happens a lot," adds Peters.

Uses of GIS

There's no shortage of examples to illustrate how GIS can be used to address urban issues. At its simplest level, GIS can produce maps that are an integral part of the master planning process. GIS can also be used for land and capacity analysis, build-out analysis, neighborhood planning and viewshed and watershed modeling.

Many municipalities made the leap to GIS by starting with parcel data and maps. Discussions of security in urban areas used to focus on the safety of pedestrians, but today we're talking about a much broader definition that includes terrorist activities and homeland security, and GIS is enabling urban areas to address these issues. GIS can also significantly reduce the amount of time it takes to handle day-to-day tasks, such as issuing construction permits, assessing property values, and accessing information about a specific parcel.

Virtually every city has had to address the issue of abandoned areas in or around their downtowns. The shift toward suburbia in the last several decades has left many vacant buildings and many others sorely in need of repair. Many urban design projects focus on these "brownfield" areas as a way to enhance the visual appeal and economic stability of a community. Many brownfield sites are contaminated, and an extensive amount of environmental data needs to be collected. GIS can help manage this data, evaluate different design alternatives and present the information to the public. ESRI has a number of case studies that illustrate how different cities and organizations are using GIS.

In San Antonio, Texas, planners are exploring alternative build-out plans based on public input. City planners in Las Vegas are preparing a comprehensive master plan to guide future urban planning and land-use decisions. The city is growing at a rate of about 30,000 people per month, and trying to plan for this growth in an organized manner has proven to be quite a challenge. A community vision survey and GIS modeling approaches are being used to help create a master plan. The GIS models will be used to visualize and predict policy outcomes and to evaluate the effects of land use, air quality, sound, transportation and property tax assessment changes.

The goal of the USGS (U.S. Geological Survey) Urban Dynamics Program is to provide a greater understanding of land-use changes that occur in urban areas. The program analyzes land-use changes, provides a historical perspective for these changes and helps assess their impact. USGS scientists use historic maps, aerial photographs and Landsat satellite data to create urban land-use databases that reflect several decades of change. These databases are then used to analyze the effects of urbanization on the landscape and to model urban growth and land use change under alternative growth scenarios. The program also develops and refines methods for land-use reconstruction, geographic analysis, modeling and impacts assessment.

For its Upper Cahaba Watershed Study, EDAW used GIS to help identify areas in a 550-square-mile watershed that needed to be protected to ensure water quality. The watershed includes the suburban spread from the city of Birmingham, Alabama, where subdivisions are being developed at an alarming rate. The first part of the study focused on how to work with such a large study area and how to identify the natural conditions of the land that made it susceptible to development. Using GIS was the only way to get a handle on the natural and physical characteristics of the watershed.

"By identifying which areas were the most sensitive, we could explore options such as cluster development that would preserve these areas, or make sure that any development met very strict standards," says Peters.

The objective of the Federal Highway Administration's TCSP (Transportation and Community and System Preservation) pilot program is to improve transportation infrastructure while reducing infrastructure costs and environmental impacts. GIS-based tools enhance project design and development, construct alternative growth and transportation scenarios and forecast potential impacts on the community. GIS land-use data has also been used to test specific impacts such as infrastructure costs, water use and exposure to pollutants.

PlanBuilder is a Web-based planning system developed by the Georgia Department of Community Affairs. It is intended to make it easer for communities to develop comprehensive plans and to get citizens involved in the design and planning process. The basic idea is that communities in Georgia can share data, information and knowledge with other communities and learn from the successes and mistakes of others. PlanBuilder includes geospatial data from a variety of sources as well as papers, reports and links to Web sites. Many documents that were once provided in hard-copy format are now available online. This greatly reduces the cost of making the documents available.

Gigalopolis is a research project by the National Center for Geographic Information and Analysis that focuses on urban settlements and their connectivity. It is based on the idea that urban issues must be addressed at a global scale because of their affect on natural resources. The project uses an environmental simulation model of urban growth called SLEUTH that seeks to predict changes in urban settings. It has been successfully implemented in cities such as Atlanta, Chicago, San Francisco, New York, Detroit, Seattle, Tampa and Mexico City, just to name a few.

Public Involvement

In urban design and planning, one difficulty is that a community is made up of people of different ages, races, religions, interests and values. Urban design and planning decisions need to address the concerns of all of these people. Urban design is a highly collaborative process because it has to address a diverse constituency.

GIS helps to communicate planning decisions to the public. Providing accurate information and opening up a two-way line of communication between planners and citizens can result in greater levels of involvement and interaction.

The integration of GIS and the Web has greatly changed how the public becomes involved with the design and planning process. Information can be shared easily, and many Web sites are set up so that constituents can add information and provide input on any project or policy decision. These sites can also function as digital town halls where the community can exchange thoughts and ideas. Some communities schedule virtual town meetings so the discussion is more interactive.

Web-based applications that convey GIS information can also help demystify the design and planning process. One problem with using GIS is that too often the process is not transparent, so it can be confusing. The only things citizens see are final maps, and they alone are not enough to convince them accept the ideas that underlie the final maps.

Future Trends

What is the future of GIS in urban design and planning? As urban problems increase in complexity, the need to access spatial data will continue to increase. You can expect to see interested stakeholders take a more active role in how their community is designed and built. Programs like Google Earth and Virtual Earth will help democratize geospatial data by allowing individuals to input information about their particular homes and businesses.

Urban growth simulations and predictive modeling can be used to help get a better understanding of how a community may grow over time, and GIS tools can help identify preferred alternative scenarios. Perhaps one day we will be able to explore the impacts of urban design and planning decisions just like we would in interactive simulation games such as Sim City.

One of the biggest benefits of GIS is that it allows urban designers and planners to be more proactive in determining what is beneficial for a community. Because of the size and complexity of many urban design projects, they may span many years. A major transportation project, for example, typically takes anywhere from 5 to 10 years to complete. GIS helps maintain a level of continuity throughout the life of a project and can even be used to tweak a project because of changes in the surrounding urban fabric.

Up to now, GIS has been much more a planning tool than a design tool. ESRI is trying to get more designers to use GIS. "We have a partnership with ESRI to develop more tools that are geared more specifically to designers," says Peters. ESRI and EDAW are working together to develop long-term prototype projects that allow urban designers to really take advantage of GIS.

James L. Sipes is the founding principal of Sand County Studios in Seattle, Washington. Reach him at jsipes@sandcountystudios.com.


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