Applied Geographic Studies最新文献

Environmental impact assessment (EIA) is a decision-making process created to incorporate environmental concerns into the procedures that guide land development and contribute to orderly environmental change. As a decision tool, EIA consists of a series of administrative requirements and analytic techniques that function to disclose the potential consequences of a proposed action before an irreversible commitment of resources is made. GIS has also been described as a decision tool that allows analysts to address complex environmental problems similar to those encountered in EIA; however, its direct application to the procedures that explain the environmental impact assessment process have not been critically examined. This article explores the nature of EIA, identifies common approaches to EIA that can be automated with the use of GIS, and describes an implementation strategy to guide the expanded application of GIS in the environmental impact assessment process. © 1998 John Wiley & Sons, Inc.

Multiple-season and multiple-year satellite remote sensor data were used to monitor and model wetland successional changes in Par Pond on the Savannah River Site, South Carolina, caused by the 19-ft (approximately 6 m) drawdown of the freshwater reservoir's water. The analysis of seven land-cover maps from March 14, 1992 through October 25, 1994 and ten change-detection maps derived from the remote sensor data quantitatively documented the spatial distribution of the successional changes in land cover. Polynomial equations fit to the successional land cover information may be used to predict the percent (and hectares) of spikerush, old field, and pine/hardwood vegetation present on exposed terrain at specific dates since drawdown. © 1997 John Wiley & Sons, Inc.

To investigate variations in residential mobility within the Southern (Third World) city, a sample questionnaire survey was undertaken in Port of Spain, Trinidad & Tobago. This survey indicated that, unlike the pervading characterization of high movement rates within such cities, suburban residents exhibited a marked stability in terms of their housing relocations. Such non-fluidity was underlined by the reluctance of these peripheral dwellers to migrate abroad, even during difficult economic circumstances. This limited movement reflected their attachment to place, country, family, or land; such bonds resulted in highly restricted rates of residential mobility in the outer parts on such Third World cities. © 1997 John Wiley & Sons, Inc.

Active microwave remote sensing techniques have been shown to be effective in measuring moisture levels at the soil surface. As synthetic aperture radar (SAR) data from satellites increasingly becomes available, the potential exists to repetitively monitor soil moisture conditions over large areas. Here, multitemporal ERS-1 SAR imagery were integrated with digital terrain data, vegetation measurements, and precipitation records to: (1) quantify and reduce the effect of variable terrain on SAR image digital number (DN) values, (2) isolate the amount of soil-contributed backscatter (σ_SOIL⁰) from the total backscatter coefficient (σ_TOT⁰), and (3) qualitatively examine the relationship between σ_SOIL⁰ and surface soil moisture conditions over tallgrass prairie subjected to varying treatments of prescribed burning. Local incidence angle (LIA) was found to have the strongest influence on SAR image backscatter values (r = 0.341). An empirically derived correction function based on the least squares estimate of σ_TOT⁰ and LIA data pairs improved image quality by more than 11%. A simple cloud model is then used to calculate the amount of radar energy backscattered by the vegetation canopy (σ_VEG⁰) in both burned and unburned watersheds. Subtracting σ_VEG⁰ from σ_TOT⁰ provides the estimate of σ_SOIL⁰. Unburned watershed σ_SOIL⁰ was significantly lower than that of burned watersheds, due to the higher density of scattering particles causing elevated σ_VEG⁰ values in these areas. At watershed and larger scales, changes in σ_SOIL⁰ reflected temporal changes in surface soil moisture levels inferred by local precipitation measurements and water budget consideration. © 1998 John Wiley & Sons, Inc.

With the rapid increase in spatial data, especially in the NASA–EOS (Earth Observing System) era, it is necessary to develop efficient and innovative tools to handle and analyze these data so that environmental conditions can be assessed and monitored. A main difficulty facing geographers and environmental scientists in environmental assessment and measurement is that spatial analytical tools are not easily accessible. We have recently developed a remote sensing/GIS software module called ICAMS (Image Characterization And Modeling System) to provide specialized spatial analytical tools for the measurement and characterization of satellite and other forms of spatial data. ICAMS runs on both the Intergraph–MGE and the Arc/Info Unix and Windows–NT platforms. The main techniques in ICAMS include fractal measurement methods, variogram analysis, spatial autocorrelation statistics, textural measures, aggregation techniques, normalized difference vegetation index (NDVI), and delineation of land/water and vegetated/non-vegetated boundaries. In this article, we demonstrate the main applications of ICAMS on the Intergraph–MGE platform using Landsat–Thematic Mapper images from the city of Lake Charles, Louisiana. Through the availability of ICAMS to a wider scientific community, we hope to generate various studies so that improved algorithms and more reliable models for environmental assessment and monitoring can be developed. © 1998 John Wiley & Sons, Inc.

This study analyzed the geographic distribution of nurse practitioners in the United States. Primary data on nurse practitioners were obtained from State Boards of Nursing and the District of Columbia in the spring of 1994. At the state level, nurse practitioners were more concentrated in urban areas than their physician counterparts. Of the 33,094 certified nurse practitioners, 85% were in metropolitan areas. Results from the dissimilarity indices between nurse practitioners and general populations showed that a greater supply of nurse practitioners in a state may not necessarily lead to an equitable distribution across counties. At both the state and county levels, the supply of nurse practitioners was positively associated with the supply of primary care physicians. Results from multivariate analyses show that nurse practitioners were more likely to locate in a county where state laws allowed independent practice. States that allow independent practice and direct third-party reimbursement will likely have greater availability and a larger supply of nurse practitioners in rural counties. © 1997 John Wiley & Sons, Inc.

Recent public interest in the environmental problems faced by communities in the Mexico/U.S. border region has led to increased efforts to assess technological hazards and emergency response capabilities. This research explores the use of geographic information systems (GIS) to evaluate emergency response capabilities relative to risk zones in Nogales, Sonora and Nogales, Arizona. The GIS allows capability assessment at a detailed level of spatial resolution, allowing planners to identify areas in the community with inadequate emergency-response facilities. Civilian evacuation scenarios, based on simulated hazardous material releases, identify network bottlenecks and other vulnerabilities. Finally, GIS allows easy visualization of these problems, thus aiding planners in identifying areas for improving emergency capabilities. © 1998 John Wiley & Sons, Inc.