GIS Goes Green

Jennifer Black, Paula Lazrus, Frank LoPresti, and Ben Winter

Environmental sustainability has been a hot topic around the globe for some time, and researchers are working hard to find ways to understand and protect complex environmental processes. This work requires careful planning, evaluation, and monitoring, some of which relies heavily on the use of Geographic Information Systems (GIS).

GIS enables researchers to link different kinds of information with spatial or geographic data, such as locations on a map, a person’s address, streets, or altitude. Different pieces of information can be layered within the same database to make maps, model spatial processes, or gain a better understanding of how complex data work together. Though GIS tools are often used to make maps, they can also be used to perform sophisticated analyses, build databases, link spatial information, and measure and model relations between different spatial points.

Modeling the Environment

The availability and management of clean water is a key ecological concern being addressed by researchers using GIS tools. Measurements of vegetation ground cover, water depth and flow speed, soil composition, slope, and altitude are gathered continually by satellites and fly-overs and made into “raster layers”. These grids of raster information, in which each square contains a specific measurement (e.g., soil type), create a checkerboard covering a geographic area and are used by various state, national, and international agencies.

Scientists use the data in these layers to model the impact of changes in environmental variables, such as transformations of the slope of hills due to strip mining, which leads to increased erosion. These models become simulation tools in GIS packages. Simulations such as the Water Erosion Prediction Project (WEPP) model allow researchers to predict erosion and mud slides, and then layers of soil, vegetation type, slope data and other factors can be studied to understand their impacts on catastrophic but predictable events.¹

Another type of research using GIS tools measures ecological problems by analyzing pollution sites and the profiles of individuals whose health is impacted by the location of these sites. Zvia Naphtali, co-author of “Using GIS to Examine Environmental Injustice in the South Bronx”² introduces her paper by stating:

The U.S. Environmental Protection Agency defines environmental justice as “...the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.”

Environmental injustice has been defined as the disproportionate exposure of communities of color and poor people, or other vulnerable groups, such as children and the elderly, to environmental risks. As part of an environmental injustice study, GIS can aid in assessing hazardous pollutants surrounding specific sites. For example, “buffers” can be created around specific geographic areas to study the extent of the measurable pollutants near that site. Mappings of poisonous air or water can be overlaid with various types of data, including census measures and demographic data.

Footnotes

For more information on the Water Erosion Prediction Project (WEPP), see http://topsoil.nserl.purdue.edu/nserlweb/weppmain/.
Available online at www.nyu.edu/its/pubs/connect/spring07/naphtali_gis.html.

Four Examples

Researchers use GIS in interdisciplinary studies to explore possible links among poverty, deforestation, flooding, population growth, industrialization, and government policies. The items that follow feature several NYU researchers who explore ways that different uses of GIS and mapping can help us better understand our world and our impacts on the environment.

Food and Nutrition – Linking New Yorkers to Local Food

Jennifer Black

Food production often tops a sustainability agenda. How and where food is grown, processed, and transported has serious implications for the environment and the health of the consumer, and eating locally-grown food is one strategy for minimizing environmental impact. Proponents argue that purchasing food grown closer to home supports regional economies, protects small farms and local jobs, promotes sustainable growing practices, and reduces environmental impact by saving on the amount of fuel needed to transport food long distances.

Farmers’ markets are one of the best ways to get fresh, local produce in New York City. The New York Department of Agriculture and Markets maintains a database of farmers’ markets throughout the state.¹ The New York City Coalition Against Hunger (NYCCAH) has created the Poverty & Food Access Map, an ideal example of how GIS technologies can be used in understanding the food system.²

The New York City Coalition Against Hunger’s Poverty & Food Access Map, an excellent example of how GIS may be used to aggregate poverty rates, population density, demographic information, and other data to better understand the food system in a specific geographic area.

Footnotes

Understanding Landscapes

Paula Lazrus

Though complex, ArcGIS (a GIS software suite used at NYU) provides even a novice with new and stimulating ways to understand the landscape and environmental changes. For example, the ArcGIS tools can assist in the planning of sustainable agricultural projects, help with the evaluation of environmental impacts after natural disasters, and provide insight into the general topography of an area as an aid to creating a thoughtful plan for building new structures.

The images in Figures 1-3 illustrate a first attempt to understand a multifaceted, changing landscape as part of a research project examining landscape and social change in southern Calabria, Italy. By combining aerial photos, archival data (for locality boundaries in Figures 3 and 1), topographical maps, and digital contour data, it was possible to create a 3-D model that allows viewers to change position within the landscape and get a sense of its shape and contour.

The elevation data, built from the contour file, is extruded to create the “tin” map (Figure 3) which is then placed beneath the photos, polygons, and maps, where it invisibly “sits” and pushes the appropriate areas “up” in ArcGlobe, part of the ArcGIS suite of software (Figures 1 and 2, below). The vertical distance has been exaggerated by a scale of 1.5 to highlight the changes in the terrain.

In Figure 1, which looks northward toward the town, locality boundaries based on archival data are marked. The large and small concentric boundaries (marked in red arrows) represent the upper town, as well as 1 and 2 km distances from the town. This image can aid in understanding the distance and difficulty of travel for people who cultivate crops in these areas.

Figure 2 reverses the view looking from town to the sea and includes views of the topographical maps, making more evident the position of the town and its territory within the landscape.

Figure 1. View of terrain built over “tin” map.

Figure 2. Alternate view of terrain.

Figure 3. “Tin” map, built on elevation data.

Sustainability and Commuting

Ben Winter

Designing cities that permit residents to commute by foot, bicycle, or public transportation helps to decrease the amount of harmful automobile emissions and reduce impact on the environment. These graduated circle maps easily convey which regions of the United States have better sustainable transportation alternatives, based on data from the 2006 American Community Survey (conducted by the U.S. Census Bureau). Researchers usually convey descriptive data like these with charts and graphs; however, user-friendly GIS software provides an easy way to display the spatial aspect of data.

The maps below show that the greater New York/New Jersey area ranks first in commuters who drive to work; however, the area also ranks first both in commuters using public transportation and those walking to work. The highest number of commuters who take their bicycle to work is found in the Santa Barbara/Santa Maria/Goleta, California region.

Note on the data: Since this survey sampled three million Americans from geographic areas that contain more than 65,000 people, the data are actually estimates of the reported populations. The maps only show data from the 125 most populated CBSAs¹ in the U.S.

Footnotes

The term “core based statistical area” (CBSA) refers collectively to metropolitan and micropolitan statistical areas. For more information, visit www.census.gov/population/www/estimates/00-32997.txt.

Global Warming

Frank LoPresti

Global warming as it relates to rising water levels is a prominent concern of environmental scientists. These maps, from a series of maps I’ve created using freely available data around the issue of global warming, show the changes that would occur along the East River with rising water levels.

The New York State GIS Clearinghouse¹ is an archive where the State and its counties deposit and retrieve map data. To create these maps, we used raster altitude data produced and made available by the Clearinghouse. They are housed in the Cornell University Geospatial Information Repository (CUGIR), an active online repository in the National Spatial Data Clearinghouse program. These data and other map datasets are available to researchers.² CUGIR provides geospatial data and metadata for New York State, with special emphasis on those natural features relevant to agriculture, ecology, natural resources, and human-environment interactions.

Bytes of the Big Apple,³ a family of software, data, and geographic bas map files for the City of New York available for download from the Department of City Planning, provides street shape map files for New York City’s political and administrative districts. Much of the map data, including the street maps used in this global warming series, is available at no cost.

Present sea level in the East River, near the Williamsburg neighborhood in Brooklyn.

Map depicting the East River near Williamsburg after a four-meter rise in sea level.

Footnotes

www.nysgis.state.ny.us
Contact data.services@nyu.edu for more information.
www.nyc.gov/html/dcp/html/bytes/applbyte.shtml

Author Biographies

Jennifer Black is a Registered Dietician; a doctoral candidate and adjunct instructor of Community Nutrition in the Department of Nutrition, Food Studies, and Public Health at NYU’s Steinhardt School of Education, Culture, and Human Development; and a senior aide in the ITS Data Services Statistics & Mapping Lab.

Paula Kay Lazrus is an anthropologist, archaeologist, and assistant professor at St. John’s University. Her research interests include the study of settlement and landscape studies with a focus on human interaction with the environment in the past, as well as issues regarding the looting of antiquities and the preservation of cultural resources.

Frank LoPresti is a Senior Faculty Technology Specialist for ITS Data Services.

Ben J. Winter is pursuing a master’s degree in Urban Planning at NYU’s Robert F. Wagner School of Public Service. He is a research assistant at NYU’s Furman Center for Real Estate and Urban Policy and works part-time as a GIS tutor for NYU faculty and students.