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Delaware River Basin Project

Regional Assessments of Land-Use Change in the Delaware River Basin

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Delaware River Basin Project Home Page

Links to individual projects:
Modeling Urban Expansion in the Philadelphia Metropolitan Area; A Cellular Automata Approach
Historical land-use data from the twentieth century was used as input to the SLEUTH land-use change model, a Cellular Automata model developed by Keith Clarke at the University of California at Santa Barbara, to produce projections of urban expansion in the Philadelphia metropolitan area.

Twentieth-Century Land Surface Changes in the Delaware Water Gap Basin, a GIS Snapshot Approach
Methods of integrating land-surface data and measuring change with time are being tested on historical land use/land cover data of the Delaware Water Gap watershed area in Pennsylvania.

The confluence of the Delaware and Lehigh Rivers.

This long-term U.S. Geological Survey project consists of a number of individual studies applying spatial analysis methods to long-term land-cover change in the Delaware River Basin, particularly in Pennsylvania. The objectives for these projects are to address and quantify predominant affects and outcomes of land-surface change in urbanizing areas. Land-use and land-cover changes affect local residents most directly, but cumulatively, contribute to regional and global changes in natural systems and quality of life. These outcomes have direct impacts on the natural resources that support the health and integrity of human beings, our environment, and our future welfare.

Overview of the Research Projects

Although each project has its own specific objectives, approaches, context, and outcomes, certain concepts are common to them all. A short summary of these concepts is discussed below.

Geospatial Data

The data for the long-term study of the Delaware River Basin primarily relies on the historical topographic maps the USGS published throughout the twentieth century. The primary challenges for building data bases from these sources include data categorization, its integration with other environmental or social data, and problems of resolving data captured at different scales. More specific discussion of these topics is available in a paper on methods for using historical USGS maps for environmental research. (Download the free Adobe Reader.) Where possible, the data files from these studies can be obtained via the Internet or by contacting the USGS contact person listed below. A graphic index of the quadrangle outlines (by latitude and longitude coordinates) and names together with the map edition timelines is available to assist the identification and selection of data files. Some supplementary data, described under the heading of the specific project, are also available.

Geospatial Technologies for the Study of Temporal Change

The data used in analyses of change with time require the support of logical concepts in space-time continuity in their methods of use. We are examining recent research on temporal change data models for the organization of disparate data sources with time for their effectiveness in representing structure of land-surface change the way we understand it.

Spatial analysis and modeling

Methods of spatial analysis test geographic data for statistically significant patterns, though the added variable of location causes these tests to differ from normal statistics. Besides widely accepted methods such as Regression and Dimensional Analysis, tests are applied to geographical point-pattern, network/path, and regional/shape structures. Some of the most important of these are spatial autocorrelation, accessibility and interaction, matrix analysis, and methods applied to spatially continuous data. Significant findings of spatial analysis lend their mathematical formalizations to statistical/mathematical modeling. The mathematical tests that are applied to organized empirical data are used for either explanatory or predictive (projection) purposes, but some modeling objectives also can be achieved through the topological manipulation of the map-like layers of geographical information systems (GIS).

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