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PubMed2002

New perspectives on the use of Geographical Information Systems (GIS) in environmental health sciences.

At first glance, the domain of health is no typical area to applicate Geographical Information Systems (GIS). Nevertheless, the recent development clearly shows that also within the domains of environmental health, disease ecology and public health GIS have become an indispensable tool for processing, analysing and visualising spatial data. In the field of geographical epidemiology, GIS are used for drawing up disease maps and for ecological analysis. The striking advantages of GIS for the disease mapping process are the considerably simplified generation and variation of maps as well as a broader variety in terms of determining a real units. In the frame of ecological analysis, GIS can significantly assist with the assessment of the distribution of health-relevant environmental factors via interpolation and modelling. On the other hand, the GIS-supported methods for the detection of striking spatial patterns of disease distribution need to be much improved. An important topic in this respect is the integration of the time dimension. The increasing use of remote sensing as well as the integration into internet functionalities will stimulate the application of GIS in the field of Environmental Health Sciences (EHS). In future, the integration and analysis of health-relevant data in one single data system will open up many new research opportunities.

Ecology↗
PubMedDate not supplied

Linking public health data using geographic information system techniques: Alaskan community characteristics and infant mortality.

This article identifies geographical contexts important in differentiating infant mortality in Alaska and uses spatial processing models to link and analyse multi-source data. Information characterizing geographical locations are collected from Alaska's vital statistics for the years 1982-91 and the 1990 Census. Geographic information system (GIS) techniques are applied to identify spatially homogeneous regions, assess spatial compatibility across databases, and allocate geographical units across boundaries. A primary goal of this paper is to encourage spatial linkage and analysis techniques for vital statistics and census data. By demonstrating the interplay of tabular, graphical, and mapping techniques on Alaskan infant mortality, this analysis describes procedures for conducting epidemiological research with data spatially defined at distinct geographical levels.

Alaska↗
PubMed2003

A geographical information system model for creating bioclimatic maps - examples from a high, mid-latitude city.

This paper presents a method for creating large-scale bioclimatic maps with the aid of a geographical information system, GIS. Meteorological data are linked with geographical information about land use, elevation and distance to the coast, in order to generate spatial distributions of physiological equivalent temperature, PET. The model combines an air temperature map and a wind map in order to create different zones for which the thermal component is to be calculated. The advantage of the model presented is that it uses generally available information about land use, altitude and distance to the coast. Further, the model uses a GIS application, which makes it non-static. Compared to most other models, a wide range of observations are used as input. Few biometeorological studies have been performed in high-latitude areas. This paper presents bioclimatic maps for the Göteborg urban area, in Sweden, for the month of July. The results show large variations in PET during a clear, calm day at 1200 hours (Delta T 13.4 degrees C) and during average conditions in July (Delta T 6.8 degrees C), which gives an indication of the magnitude and the spatial variations within high, midlatitude, urban area in summer. The highest PET values were found in the central built-up areas and the lowest PET values in the coastal and green areas. The model generates valuable information for urban planners and decision makers when planning and constructing new areas for outdoor activities etc. This information is also useful in the fields of health and energy.

Cities↗
PubMed2004

Delineation and evaluation of hydrologic-landscape regions in the United States using geographic information system tools and multivariate statistical analyses.

Hydrologic-landscape regions in the United States were delineated by using geographic information system (GIS) tools combined with principal components and cluster analyses. The GIS and statistical analyses were applied to land-surface form, geologic texture (permeability of the soil and bedrock), and climate variables that describe the physical and climatic setting of 43,931 small (approximately 200 km2) watersheds in the United States. (The term "watersheds" is defined in this paper as the drainage areas of tributary streams, headwater streams, and stream segments lying between two confluences.) The analyses grouped the watersheds into 20 noncontiguous regions based on similarities in land-surface form, geologic texture, and climate characteristics. The percentage of explained variance (R-squared value) in an analysis of variance was used to compare the hydrologic-landscape regions to 19 square geometric regions and the 21 U.S. Environmental Protection Agency level-II ecoregions. Hydrologic-landscape regions generally were better than ecoregions at delineating regions of distinct land-surface form and geologic texture. Hydrologic-landscape regions and ecoregions were equally effective at defining regions in terms of climate, land cover, and water-quality characteristics. For about half of the landscape, climate, and water-quality characteristics, the R-squared values of square geometric regions were as high as hydrologic-landscape regions or ecoregions.

Climate↗
PubMed2004

Use of remote sensing and geographical information systems to identify environmental features that influence the distribution of paramphistomosis in sheep from the southern Italian Apennines.

A geographic information system (GIS) was constructed using remote sensing (RS) and landscape feature data together with Calicophoron daubneyi positive survey records from 197 georeferenced ovine farms with animals pasturing in a 3971 km(2) area of the southern Italian Apennines. The objective was to study the spatial distribution of this rumen fluke, identify environmental features that influence its distribution, and develop a preliminary risk assessment model. The GIS for the study area was constructed utilizing the following environmental variables: normalized difference vegetation index (NDVI), land cover, elevation, slope, aspect, and total length of rivers. These variables were then calculated for "buffer zones" consisting of the areas included in a circle of 3 km diameter centered on 197 farms. The environmental data obtained from GIS and RS and from data taken by the veterinarians on the field (stocking rate and presence of streams, springs and brooks on pasture) were analyzed by univariate (Spearman and ANOVA) and multivariate (discriminant) statistical analyses using the farm coprological status (positive/negative) as the dependent variable. Sheep on 32 of the 197 (16.2%) farms, were positive for C. daubneyi, with an average intensity of 52 epg. A multivariate stepwise discriminant analysis model was developed that included moors and heathland, sclerophyllous and coniferous forest vegetation, autumn-winter NDVI and presence of streams, springs and brooks on pasture. The variables entered in the model were also correlated with C. daubneyi positive farms in the univariate tests and are consistent with the environmental requirements of C. daubneyi and its snail intermediate host.

Animals↗
PubMed1994

Using a geographic information system to understand child pedestrian injury.

Data from police accident reports involving pedestrians less than 20 years of age in Hartford, Conn, during 1988 through 1990 were abstracted and entered into a geographic information system. Two high-frequency collision areas were identified and compared. There were 374 child pedestrians involved in collisions (a rate of 28 per 10,000). Two high-occurrence areas accounted for 30% of collisions. Collisions in one of these areas were more likely to involve younger children (8.1 vs 10.2 years of age) and to occur in the late afternoon, and occurred closer to the child's residence, than collisions in the other area. The geographic information system is a useful tool in the study of child pedestrian collisions.

Accidents, Traffic↗
PubMed1999

Use of a geographic information system to determine appropriate means of trauma patient transport.

OBJECTIVE: To determine whether a geographic information system (GIS) and historical transport data can be used to create a map that identifies locations (zones) from which either ambulance or helicopter transport will result in shorter out-of-hospital times. METHODS: A retrospective, cross-sectional review of a trauma registry was conducted in a two-county region served by a single trauma center. Data were gathered for all patients transported directly to the trauma center between 1993 and 1996. Incident locations and times from first 911 contact until arrival at the trauma center (out-of-hospital time) were extracted. A GIS was used to create a reference map with all incident locations plotted and given z-coordinates corresponding to out-of-hospital time. Two contour surfaces were interpolated: one for all helicopter transports and one for all ground transports. Areas where the helicopter surface was lower than the ambulance surface were designated air zones since helicopter transport resulted in shorter out-of-hospital times. The remaining area was designated a ground zone since ambulance transport resulted in shorter out-of-hospital times. The mean out-of-hospital times were calculated for each mode of transport in both zones and were compared using a two-tailed t-test. RESULTS: An air zone was identified beginning between 5 and 16 miles from the trauma center. Mean (+/-SD) out-of-hospital time from the air zone was 50 +/- 9 minutes for helicopter transport (n = 54) and 63 +/- 14 minutes for ambulance transport (n = 140). The difference between the means was 13 minutes (p < 0.000001; 95% CI = 8.95 to 17.05). Mean out-of-hospital time from the ground zone was 68 +/-16 minutes for helicopter transport (n = 122) and 32 +/- 14 minutes for ambulance transport (n = 2,047). The difference between the means was 36 minutes (p < 0.000001; 95% CI = 33.59 to 38.41). CONCLUSIONS: A GIS and historical transport data can be used to create a map identifying locations from which either helicopter or ambulance transport will minimize out-of-hospital time. Inappropriate choice of transport mode is associated with increased out-of-hospital time.

Aircraft↗
PubMed2003

[Spatio-temporal problems of geographic information system in marine fishery].

In marine fisheries, it is very important to understand and grasp the spatio-temporal nature. Geographical Information System (GIS) has been applied to describe or forecast the dynamic trend of resources or to set up evaluation model, which is one of high technologies in modern marine fisheries. Based on the review of the development of marine fishery GIS (MFGIS), four spatio-temporal problems it occurred were discussed, and the possible resolutions were prospected.

Animals↗
PubMed1990

Geographical information systems for studying the epidemiology of cattle diseases caused by Theileria parva.

Data on selected variables which influence the epidemiology of cattle diseases caused by Theileria parva were assembled and entered in a computerised geographical information system. Variables studied included the distributions of major hosts (cattle and buffalo), the vector ticks (Rhipicephalus appendiculatus and related species) and the reported presence of East Coast fever, corridor disease and January disease. In addition, the distribution of climatic suitability for R appendiculatus was assessed using the model CLIMEX run on an interpolated climate database developed for Africa. Distribution maps of each variable were produced. The potential value of geographical information systems in studies of disease epidemiology and control is discussed, with examples of how sensitivity may be enhanced by the inclusion of additional variables. In addition, subject areas in which poor data quality and inadequate data standardisation may limit the use of these systems are identified and discussed.

Africa↗
PubMed2006

Epidemiological study of Q fever in humans, ruminant animals, and ticks in Cyprus using a geographical information system.

A cross-sectional study of Q fever was conducted in a representative sample of the human and animal population in Cyprus in order to assess the seroprevalence of Q fever and the prevalence of related risk factors. A total of 583 human and 974 ruminant animal serum samples were collected and tested for the detection of antibodies against Coxiella burnetii phase II antigen using an indirect immunofluorescent assay. One hundred forty-one ticks were collected from the infested animals examined; the polymerase chain reaction and the shell-vial technique were used to detect and isolate C. burnetii. Standardized questionnaires were used to obtain information concerning inhabitants and their animals. A geographical information system was used to identify high-risk regions. The prevalence of IgG antibodies against C. burnetii phase II antigen was estimated at 52.7% for humans, 48.2% for goats, 18.9% for sheep, and 24% for bovines. C. burnetii was detected in 11 (7.8%) ticks. Using the geographical information system, two villages were identified as high-risk regions on the basis of high seroprevalence rates of IgG antibodies in humans and animals. Risk factors related to Q fever seropositivity were identified by logistic regression analysis and included age, residence, occupation, use of manure in the garden, ownership of animals (especially goats), and the presence of tick-infested or aborting animals. Q fever poses an occupational hazard to humans living in close contact with sheep and/or goats. In parallel, ticks should be considered an important aspect in the epidemiology of Q fever and should be further studied to better elucidate their role.

Adolescent↗
PubMed1991

Geobase: a simple geographical information system on a personal computer.

Spatially distributed data are often encountered in the biological sciences. Representation and analysis of such data requires specific tools. A simple geographical information system is presented, which allows representation and elementary analysis of geographically coded information. The system handles two kinds of data: maps and facts, where map data describe the basis on which the fact data are located. Maps consist of objects described through a set of coordinates, while for facts a coordinate pair is associated with an unlimited number of data records containing five fields: a date, an element from a list, a two-character code, an integer number and a real number. The input data can be displayed interactively on screen by logically combining selection criteria for each field. The facts corresponding to the selected criteria are either displayed as such, or are clustered and displayed as polygons or pies. A short example showing a possible application of the program is presented and advantages as well as limitations are discussed.

Algorithms↗
PubMed2000

Spatial statistics and geographical information systems in epidemiology and public health.

This chapter surveys the principles behind spatial statistics and geographic information systems (GIS), and their application to epidemiology and public health. Like the other introductory chapters, it is aimed mainly to facilitate understanding in the chapters specific to certain diseases that follow, and to provide a short introduction to the field. A brief overview of spatial statistics and GIS is provided in the introduction. The sections that follow explore the ways in which we can map the distribution of disease, ways in which we can look for spatial patterns in the distribution of disease, and ways in which we can apply spatial statistics and GIS to the problem of identifying the causal factors of observed patterns. In the last section I discuss some of the ways in which these techniques have been applied to assist decision making for disease intervention, and conclude by discussing future developments in the field, and some of the issues surrounding the integration of spatial statistics and GIS.

Animals↗
PubMed2006

Web-based public health geographic information systems for resources-constrained environment using scalable vector graphics technology: a proof of concept applied to the expanded program on immunization data.

BACKGROUND: Geographic Information Systems (GIS) are powerful communication tools for public health. However, using GIS requires considerable skill and, for this reason, is sometimes limited to experts. Web-based GIS has emerged as a solution to allow a wider audience to have access to geospatial information. Unfortunately the cost of implementing proprietary solutions may be a limiting factor in the adoption of a public health GIS in a resource-constrained environment. Scalable Vector Graphics (SVG) is used to define vector-based graphics for the internet using XML (eXtensible Markup Language); it is an open, platform-independent standard maintained by the World Wide Web Consortium (W3C) since 2003. In this paper, we summarize our methodology and demonstrate the potential of this free and open standard to contribute to the dissemination of Expanded Program on Immunization (EPI) information by providing interactive maps to a wider audience through the Internet. RESULTS: We used SVG to develop a database driven web-based GIS applied to EPI data from three countries of WHO AFRO (World Health Organization - African Region). The system generates interactive district-level country immunization coverage maps and graphs. The approach we describe can be expanded to cover other public health GIS demanding activities, including the design of disease atlases in a resources-constrained environment. CONCLUSION: Our system contributes to accumulating evidence demonstrating the potential of SVG technology to develop web-based public health GIS in resources-constrained settings.

Databases, Factual↗
PubMed2005

Use of a remote sensing-based geographic information system in the characterizing spatial patterns for Anopheles minimus A and C breeding habitats in western Thailand.

A remote sensing (RS)-based Geographic Information System (GIS) was used to characterize the breeding habitats of Anopheles minimus species A and C in five different districts of Kanchanaburi Province in western Thailand. The GIS and RS were used to monitor the area for the presence and absence of An. minimus A and C in five major land areas, forest, agriculture, urban, water and bare land. The results show that An. minimus A survives both in dense canopy forest and in open fields where agriculture is dominant. A scatter plot of land-use/land-cover for An. minimus, considering proximities to the forest and proximities to agriculture, suggests that An. minimus A has a wider habitat preference, ranging from dense canopy forest to open agricultural fields. A scatter plot for An. minimus C, on the other hand, showed a narrow habitat preference. A scatter plot for proximities performed on separate populations of An. minimus species A, one in the north and the other in the south, showed that there was an association in the northern population with the forest and in the southern population with agricultural areas. There were no statistically significant differences in the scatter plot of proximities to urban areas and water bodies with the An. minimus A north, south, and An. minimus C. LANDSAT TM satellite data classification was used to identify larval habitats that produce An. minimus A and C and analyze proximities between land-use/land-cover classes and locations of larval habitats. An. minimus A has a wide habitat preference, from dense canopy forest to open agricultural fields, while An. minimus C has a narrow habitat preference.

Animals↗
PubMed2005

[Studies on the spatial distribution and environmental factors of highly pathogenic avian influenza in Mainland China, using geographic information system technology].

OBJECTIVE: To analyze the spatial distribution of highly pathogenic avian influenza (HPAI) and to explore environmental factors associated with HPAI using geographic information system (GIS) techniques in Mainland China. METHODS: Databases were set up using the information of HPAI during epidemics in 2004, and linked to digital maps at provincial and county administrative layers in the country through the ArcGIS 8.3 software. Spatial cluster analyses, spatial statistics analyses and tracking analyses on epidemic situation of HPAI were implemented. Environmental factors associated with HPAI were also analyzed on data related to weather, vegetation and migratory birds etc. RESULTS: Findings from spatial cluster analyses showed that high incidence area was centralized in 113.261 degrees ordm; east longitude and 23. 119 degrees ordm; north latitude with a radius of 1090.52 kilometers (relative risk= 2.646, P value= 0.001). Spatial statistical analyses showed that HPAI took place mainly in capital cities of provinces and surrounding areas as well as in the circumference areas of arterial rivers, lakes and seacoasts. Results also showed that HPAI occurrences were associated with low air temperature, high relative humidity and high air pressure as well as with east & central migration routes of migratory birds. The average normalized difference vegetation index was 0.36 +/- 0.11 in epidemic areas of HPAI. CONCLUSION: HPAI was unrandomly distributed and geographically clustered in China.

Animal Migration↗
PubMed2004

The geographic information system as an epidemiological tool in the surveillance of dengue virus-infected Aedes mosquitos.

A Geographic Information System (GIS) was used as analysis tool to study the spatial distribution of dengue virus-infected Aedes mosquitos in Thailand. Global Positioning System (GPS) instruments were used to map villages involved in dengue epidemiological studies in Ratchaburi Province, Thailand. Differentially processed GPS data, with a spatial resolution of approximately 1 meter, were incorporated into a GIS for analysis and mapping. Databases associated with a village GIS included village number, Aedes aegypti populations, and test results. Epidemiological surveillance for dengue infection through the detection of the dengue virus type(s) infecting Aedes mosquitos during epidemic periods constitutes a reliable sentinel system for dengue outbreaks. Various techniques were applied including: enzyme linked immunosorbent assay (ELISA), indirect immunofluorescent assay (IFA), and reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the virologic surveillance of the type-specific detection of dengue viruses in artificially infected and in field-caught adult Aedes mosquitos. In laboratory experiments, all assays showed sufficient sensitively to detect one virus infected mosquito and the rapid RT-PCR clearly showed serotype-specificity with very high detection sensitivity. In the field study conducted from April to September 2000, female adult Aedes mosquitos were collected from selected dengue-sensitive areas in Chom Bung district, Ratchaburi Province and assayed by ELISA, IFA and RT-PCR with 18.3% (44/240), 28.98% (20/69) and 15% (3/20) positive for dengue virus, respectively. Geographic distribution of the virus-infected Aedes mosquitos and household locations were demonstrated by the GPS and the GIS. The development of disease mapping data coupled with RT-PCR laboratory-based surveillance of dengue virus infection can successfully serve as epidemiologic tools in an early warning system for dengue hemorrhagic fever (DHF) epidemics.

Aedes↗
PubMed2003

Evaluating ecosystem management capabilities at the local level in Florida: identifying policy gaps using geographic information systems.

Because ecosystem approaches to management adhere to ecological systems rather than human-defined boundaries, collaboration across jurisdiction, agencies, and land ownership is often necessary to achieve effective management of transboundary resources. Local natural resource and land use planners increasingly recognize that while ecosystem management requires looking beyond specific jurisdictions and focusing on broad spatial scales, the approach will partly be implemented at the local level with the coordination of local policies across larger landscapes. This article evaluates the collective capabilities of local jurisdictions to manage large transboundary ecological systems in Florida. Specifically, it combines plan evaluation with geographic information systems (GIS) techniques to map, measure, and analyze the existing mosaic of management across selected ecosystems in the southern portion of the State. Visual and statistical results indicate significant gaps in the management framework of southern Florida that, if filled, could achieve a greater level of consistency and more complete coverage of ecosystem management policies. Based on the spatial distribution of 58 ecosystem management indicators, notable gaps persist in the southwest coast, southeast coast, and central Everglades ecosystems, particularly for wildlife corridors and collaboration with neighboring jurisdictions. We also test for spatial autocorrelation of ecosystem planning scores and find that local jurisdictions with strong ecosystem management capabilities tend to cluster within specific ecosystems. Based on the findings, we make recommendations on how and where local plans can be strengthened to more effectively attain the objectives of ecosystem approaches to management.

Conservation of Natural Resources↗
PubMedDate not supplied

Reconstruction and computation of microscale biovolumes using geographical information systems: potential difficulties.

Biofilms are bacterial colonies enveloped in a matrix of extracellular polymeric secretions. Confocal scanning laser microscopy has been used in conjunction with different image analysis techniques to investigate the structure of biofilms. A major goal is to reconstitute the three-dimensional structure of biofilms, and compute or estimate the biovolumes. Our previous research focused on the utilization of remote sensing techniques and Geographical Information Systems for quantitative analyses of confocal images. The present study investigates potential problems in microbial imaging, and uses two approaches, the program COMSTAT and a Geographical Information Systems-based method, to reconstitute three-dimensional structures and estimate biovolumes. Volumes of thirty fluorescent polymeric microspheres with a known diameter were estimated and used as a ground truth, to statistically compare both methods. In a next step, the two approaches were used to estimate the biovolume of a section through a Pseudomonas aeruginosa biofilm. Difficulties were encountered in image acquisition due to the optical properties of the microbeads. Our results indicate that the Geographical Information Systems approach produced results consistent with the existing COMSTAT approach, and close to theoretical values, despite many problems inherent to each phase of this process. Also, the image classification process encountered several limitations. It is suggested that the unique constraints of the microscopic world may generate additional problems, especially related to image classification.

Biofilms↗