|Year : 2017 | Volume
| Issue : 2 | Page : 94-100
Impact of geographical information system on public health sciences
Jafar Aghajani, Parissa Farnia, Ali Akbar Velayati
Mycobacteriology Research Center (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
|Date of Web Publication||23-Nov-2017|
Mycobacteriology Research Center (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran
Source of Support: None, Conflict of Interest: None
In this brief review, the geographic information systems (GISs) and its beneficial influence in the field of health were discussed and highlighted. Basically, GIS is a computerized system that can significantly add to assess and monitor the effects of environmental factors (namely, population, air pollution, location, climatic changes) on public health problems. The main benefits of GIS in health services are mapping and/or visualizing of disease distribution, which will ultimately improves our understanding of disease diversities and their spatial patterns. Therefore, GIS technology is capable of providing the intra- and inter-logical connection between health, social services, and natural environment.
Keywords: Disease mapping, geographic information system, medical geography, medical informatics, public health
|How to cite this article:|
Aghajani J, Farnia P, Velayati AA. Impact of geographical information system on public health sciences. Biomed Biotechnol Res J 2017;1:94-100
|How to cite this URL:|
Aghajani J, Farnia P, Velayati AA. Impact of geographical information system on public health sciences. Biomed Biotechnol Res J [serial online] 2017 [cited 2019 Sep 22];1:94-100. Available from: http://www.bmbtrj.org/text.asp?2017/1/2/94/219104
| Introduction|| |
Geographic information system (GIS) is a computer-based program that collects, analyzes, and stores the requested information from the specific geographic location. This system has the ability to converge informations in relation to the accommodation of population, air pollution, and climatic changes., GIS is very convenient for directional data analyses and can provide a basic framework on public health research and evaluation.,,,,, GIS structure is run with five main principles: (a) a spatially reference data that collect and store relational geodatabase, (b) a hardware tool that physically stores and collect the data, (c) a software assembling user-interface algorithms, by which users access the database, query, and analyze the data, (d) the algorithms and data management procedures, and (e) the people, who are producers and consumers of spatial data., Thereby, GIS is a database which may be used by different users to meet various information needs. This database consists of a series of information that called “layers” each of these layers contains either raw data such as topographic or satellite data or thematic data such as health services. GISs can convert spatial data into the geographic or coordinate system.,, In an environmental aspect, GIS systems could demonstrate different information in forms of maps, tables, and graphs. Using satellite maps, GIS could correlate variable information such as temperature, soil type, weather conditions with diseases distribution, and incidence in specific region. Moreover, the system would be an applicable tool for evaluating the health-care centers with outlining the possibility of new health-care facility in a suitable locations., Therefore, GIS technology is considered as a decision-making tool for various health-related problems.
Today, because of health quality awareness, the need to rapidly diagnose and evaluate public health problems become an urgent issues. In this regard, GIS with strong analytical performance would play a decisive role in health data collection and analysis. Thus, helping to evaluate the prevalence of common diseases and outline the significant impacts of diseases on the quality of life. By collecting information, GIS manages the epidemiological data, describing the severity of disease, and assess the prevalence in different geographical regions. In this article, we aim to review the importance of GIS in public health management and discuss the advancement of GIS technology over other conventional analysis.
| Historical Retrospective|| |
Hippocrates (3rd century BC) was the first medical researcher who described the relationship between the geographical characteristics of a place and its inhabitant's health. In his treatise “On Air, Water and Places,” he explained the role of weather and places to the treatment outcomes. Many years after Hippocrates, the apparent use of mapping based on environmental conditions became an important issue not only for researchers but also for clinicians. In this context, the first documented maps to present diseases-related data was in 1832 by the French geographer Charles Picquet in the city of Paris. He presented first color-coded maps for cholera distribution in 48 districts of Paris., Then, in 1840, Robert Cowan showed the relationship between crowd and incidence of yellow fever in Glasgow of England. He recognized that in the regions with too much of immigrant populations, the disease was more epidemic. Robert Perry (1843) identified the source of typhus-epidemic (1843) in affected households.,, Later on, John snow (1850) was a first modern epidemiologist who recognized the clusters of cholera-infected patients. Using dot map, he could illustrate the source of outbreaks around the public water pump in Broad Street of London. All these early data proved to be useful for understanding the diseases spread and transmission within specific regions. Although it was very time-consuming to draw the maps by hand, and the data were not very effectively reproducible. This trend changed in the 19th century. The first direct predecessor of GIS, that is, computer mapping and map analysis was designed by researchers in the United States of America (USA) in the 1960–1970., During this period, they used GIS for resource assessment, land evaluation, and planning. Among most influential studies, the investigation by Howard Fischer (1963) can be highlighted. Fischer could reproduce and print the geographical mapping system., Indeed, the years from 1960 to 1970 can be called as the first or pioneering age of GIS development in which the individual personalities were of critical importance. The second age (1973–1980s) was a regularization of experiment and practice within local and national agencies. The third phase (1982 till end of 1980s) was commercial dominance. In the fourth or current phase, GIS became a new discipline that could generate massive and comprehensive interest among vendors worldwide. Today, the field of GIS is characterized by great diversity of applications, for example, agriculture, botany, air pollution, zoology, economics, etc., As a result, the definition of GIS becomes more complex, because there are too many ways of defining and classifying objects and subjects.
With the advent of information technology, new computer systems which promote the market opportunities were developed. Among them, the use of geostatic modeling technique, gained much scientific attention.,, This model is an interpolation method that can predict the pollution level between sampling stations with spatial maps using ArcGIS software. It is observed that most of the predicted pollutants are violating the Central Pollution Control Board norms. One of the main question concerning air pollution is whether air pollution is contributing to the induction of various respiratory diseases such as asthma, chronic obstructive pulmonary disease, and tuberculosis (TB).,, For this reasons, the main substances of air pollution (sulfur dioxide, carbon monoxide, nitrogen oxides, ozone, and particulates substances) and its correlation to respiratory diseases were investigated over a fixed period of time.,,, The other improvement of GIS technology was new mapping program called “Syntonic Mapping and Analysis Program” (SYMAP). The SYMAP program underlies the achievement of a comprehensive program under the GIS. This system is capable of analyzing data based from different geographical regions.,, and could connect the experts from various epidemiological and health-care centers for producing advanced and comprehensive spatial models. Using recent advances, the new applications of GIS in health-care science have become possible, for example, the impact of environmental condition and social economical risk factors in malaria epidemics in different ethnic groups was evaluated. In 2002, the “Office of Statewide Health Planning and Development” established another powerful system for resources and facilities management. The system designed to produce conceptual model for the analysis of various relationships and their application. The ultimate goal was to cover the needs of health customers by controlling and monitoring the operational and optimization of available resources. In general, the collected data were first sent to primary health center and from there it was forwarded to Statistics Colleges for further investigation, for example, finding the best location in classified areas. Keola et al. demonstrated the combination use of statistical analysis and spatial data for decision-making of various public-related health diseases. In 2003, the “International Organization of health in Europe” proposed the benefit of using GIS for identification of diseases in areas with contaminated water resources. Early observation confirmed the importance of GIS in care and management of patients, recovering and recognizing the temporal and spatial association of disease. Similarly, another GIS strategic plan (2006) was proposed by “Environmental Protection Agency” (EPA) which had to investigate the spread of West Nile (WN) virus in Pennsylvania, USA. The WN virus is easily and quickly spread at any location and in most of the cases the Culex mosquito vector is responsible for primary transmission. Further transmission may occur through blood transfusion, organ transplantation, breastfeeding, intrauterine exposure, or by nosocomial infection.,,,, The EPA successfully demonstrated the location of virus and extent of the disease transmission in different geographical health centers using GIS. Neverthless, what has been discussed here may not cover the entire history of GIS-development, but it certainly outlines the individuals' and institutions which played a key role in the development of GIS.
| Geographic Information System Data|| |
GIS data is the primary source of information. Usually, maps are formed from pieces of information gathered from each layer. The main type of data used in a GIS environment, including areas (e.g., village), lines (e.g., roads, rivers), polygons, and boundaries of the region., Spatial data can be related to understanding of features such as spatial variation of disease, and its relationship to environmental factors and the health-care system. The World Health Organization (WHO) in the draft document of 2003, “Public Health Mapping: Inventory of Geographic Information” identifies core geographic information that are to be to used in public health programs [Table 1].
|Table 1: The introduction of geographic information used in public health programs by the World Health Organization in 2003|
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| Software Used in Geographic Information System|| |
Basically, the applications that used in public health sciences can be grouped into three distinct programs: ArcView, HealthMapper, and EpiMap. Although the entire applications used shape file format which is the most common format of data availability.
| ArcView|| |
ArcView software is a desktop version of GIS from the Environmental Systems Research Institute, Inc. (ESRI). This software is widely used by researchers and physicians worldwide. Epi analysis is an another software produced by the same company which has extensive capabilities in the field of public health. This GIS software includes a full featured program for viewing, analysis, and data management individually which can be used and/or purchased with other GIS products. Below is an overview of the software [Figure 1].
|Figure 1: A view of the Esri Web server and ArcMap software (a), Using layers and source of the ArcMap program (b)|
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| EpiMap (Part of EpiInfo)|| |
This software was produced by the Center for Disease Control, USA. This software is freely available for public health professionals. It is designed to provide and build database and to easy analysis the epidemiological statistics and provides maps and charts. Initial applications of EpiInfo includes:
- Make view: A program for creating forms and questionnaires that will automatically create a database
- Enter: A program to build forms and questionnaires in make view and import the data into the database
- Analysis: A program for the production and analysis and output statistics charts
- EpiMap: A program for creating GIS maps and overlay data
- EpiReport: A tool that allows the user to combine analysis output analysis, data entry, and data access to SQL.
The software is very user-friendly and comes with good sources for support. Translations are available in 13 other languages apart from English.
| MapInfo|| |
This is a GIS package of commercial developed and popular that not features the applications productive of ESRI Company. [Figure 2].
|Figure 2: An overview of the program Epimaps (a) and EpiInfo (b). Note: In the collection of EpiInfo and Epimap programs, you can make use of tools such as questionnaires, forms, and analysis spatial map data input|
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| HealthMapper|| |
To address medical- and health-based problems, the WHO and UNICEF were designed and developed HealthMapper service. Due to problems in GIS including difficulty in learning the software, the high cost of the software and the lack of customization features for analysis limited their usages. However, this user-friendly system is customized specifically for data management and mapping for public health users. The system facilitates data standardization, collection and updating of data on epidemiology, and visualizes real-time information in the form of maps and tables. HealthMapper includes a database of baseline geographic, demographic, and health information, including communities, health-care facilities, education, access to safe water, and demography. HealthMapper includes original features including layers of natural and environmental and infrastructure in shape file. Below is an overview of the software [Figure 3].
|Figure 3: HealthMapper program can be used for the monitor and assess diseases and their geographical connections|
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| Application of Geographic Information System in Health-care Sciences|| |
In the past few years, dramatic changes have been done in the prospects of our health and related care services. Thus, countries with strong health policies and services aimed to use GIS for the improvement of therapies leading to effective disease control. Since geography is one of the natural and inherent aspects of public health, any activity related to distribution of disease or health services in different populations have a geographic component in them. General concepts of public health activity are measured and understood through (GIS) technology. The implementation of GIS serves as the core mechanism that supports four primary functions of the public health geographic's team; spatial data creation, maintenance, geospatial analysis, map application development, and cartographic representations. The GIS technology divides into four main processes: analysis (statistics and geographic analysis, data transferring, and categories), creation (database design and data management, as well as edition of geographical data), visualization (create an insight and geovisualization and the use of maps for better understanding), and development of applications (software development, creation and development of databases on the Web, software design and support) [Figure 4]. Geographical diversity and its necessity for health-care systems needs to analyze the health services data. The uneven distributions of population, economic, and cultural diversities in different parts of the world are the most important factors that could affect the processes of GIS. In general, the use of GIS in the field of health can be summarized as following:
- Investigation of diseases and planning of interventions
- Epidemiological analysis
- Analysis of the spatial model of health-care accessibility
- Incarnation and reconnaissance analysis of epidemiological data
- Geographical correlations of health consequence.
- Environmental and collective determinants of human risk during disease indication
- Preparation and control
- Complex analysis and research
- Communication and social mobilization.
| Geographic Information System in Strategic Health-Care Plan|| |
The most important application of GIS is to domiciliary care provision. GIS is able to organize all source routes that are affecting health-care products. Since GIS have many different information it can not only improves the governmental health services but also it can promote private health services. GIS technology is highly applicable in strategic planning, research, evaluation, and emergency preparedness in health services areas., GIS can be a fantastic approach for individuals who are busy with promoting health services and delivery in different organizations all over the world. This trend will accelerate and steer patients to the appropriate health services. By examination of geographical variation of a specific area, upcoming events will be predicable, and thus a correct decision on a course of action can be made. For example, the review and analysis of data related to demographic changes in Canada between 2006 and 2011, resulted in taking right decisions on health-care problems. With this information, they could design appropriate locations for emergency stations and ambulances [Figure 5].,
|Figure 5: Mapping change of Canada population, 2006–2011 by census division|
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| Geographic Information System in Mental Health|| |
Mental disorder is an increasing health problem. It is estimated that 20%–25% of world populations are dealing with a mental illness at some point of their life., It is manifested that the GIS would be a valuable tool for health-care professionals to both treat and prevent mental illness. In addition, to investigate the accessibility of these health services is important task in GIS. For example, GIS can estimate the distribution of mental health services and explain the reasons for low reason accessibility. In a study conducted in Greece, 14–16 people suffered from mental disorder., Using epidemiological evaluation, it became clear that most of patients were suffering from stress. In other studies, a correlation was found between elderly and mental illness. Some of these mental illnesses have been intertwined completely with environmental changes or natural disasters and urbanization. Therefore, GIS can be applicable in planning new mental health services as well as evaluation of the association between mental health and geographic variables such as individual accommodation., Data related to mental health, mental illness, ethnicity, and education level of the population are available to be displayed on the GIS-generated maps., In the other words, GIS could be an appropriate solution for a wide range of environmental problems that threaten human health. This system can be as simple applications, such as analysis of the map as well as decision-making tool used to more complex issues.
| Geographic Information System and Environmental Hazard|| |
According to the WHO (2000), environmental hazards are responsible for about 25% of the total burden of disease worldwide, of which 35% occurs in Africa. It has been estimated that 13 million deaths could have been avoided if we had healthier environment. Studies have shown that cardiovascular events, including heart and stroke deaths, are associated with gaseous pollutants, especially air pollutions. GIS is able to display the dispersion and transportation of gaseous pollutants and particulates. Water and other beverage around the world are infected with chemicals. Furthermore, serious health problems occur due to the contamination of water with pathological microorganisms. Here again, GIS can effectively provide accurate information about the water contaminations to environmental health researchers. Therefore, many environment based studies such as mapping reviews epidemics are done with the use of GIS to accelerate and promote data analysis.
| Geographic Information System and Infectious Diseases|| |
GIS can help in prediction, surveillance, management, and analysis of infectious diseases. It has been shown that major causes of deaths occur because of human infection with HIV, TB, and malaria. Epidemiological analysis showed more than 95% of these deaths in the developing nations., GIS technology could very well help researchers to apply remote sensing, performance, and monitoring of these infectious diseases, worldwide.,
| Conclusion|| |
GIS technology should be considered as an important tool that is actively engaged in public health. It provides accurate information, makes robust visualization, and monitors public health-related problems. It records and displays the available resources and material in any given geographical region. In overall, GIS technology has become an essential tool that upgrades our knowledge and understanding on public health problems.
Financial support and sponsorship
This study was financially supported by Mycobacteriology Research Centre, National Research Institute of TB and Lung Disease, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Conflicts of interest
There are no conflicts of interest.
| References|| |
Partilla M. The uses of mapping in improving management and outcomes of tuberculosis control programs: An overview of available tools: Management Gement Sciences for Health; 2008. p. 1-18.
Kaminska IA, Oldak A, Turski WA. Geographical information system (GIS) as a tool for monitoring and analysing pesticide pollution and its impact on public health. Ann Agric Environ Med 2004;11:181-4.
Ward MH, Nuckols JR, Weigel SJ, Maxwell SK, Cantor KP, Miller RS. Identifying populations potentially exposed to agricultural pesticides using remote sensing and a geographic information system. Environ Health Perspect 2000;108:5-12.
Brody JG, Vorhees DJ, Melly SJ, Swedis SR, Drivas PJ, Rudel RA. Using GIS and historical records to reconstruct residential exposure to large-scale pesticide application. J Expo Anal Environ Epidemiol 2002;12:64-80.
Dabrowski JM, Peall SK, Van Niekerk A, Reinecke AJ, Day JA, Schulz R. Predicting runoff-induced pesticide input in agricultural sub-catchment surface waters: Linking catchment variables and contamination. Water Res 2002;36:4975-84.
McKelvey W, Brody JG, Aschengrau A, Swartz CH. Association between residence on Cape Cod, Massachusetts, and breast cancer. Ann Epidemiol 2004;14:89-94.
Thapinta A, Hudak PF. Use of geographic information systems for assessing groundwater pollution potential by pesticides in Central Thailand. Environ Int 2003;29:87-93.
Fletcher-Lartey SM, Caprarelli G. Application of GIS technology in public health: Successes and challenges. Parasitology 2016;143:401-15.
Bergquist R, Rinaldi L. Health research based on geospatial tools: A timely approach in a changing environment. J Helminthol 2010;84:1-11.
Fradelos EC, Papathanasiou IV, Mitsi D, Tsaras K, Kleisiaris CF, Kourkouta L. Health based geographic information systems (GIS) and their applications. Acta Inform Med 2014;22:402-5.
Comtrade UN. Department of Economic and Social Affairs/Statistics Division. UN Comtrade Database; 2006.
Abbott LT, Argentati CD. GIS: A new component of public services. J Acad Libr 1995;21:251-6.
Najafabadi A. Applications of GIS in health sciences. Shiraz E-medical J 2009;10:221-30.
Manolitzas P. Effective Methods for Modern Healthcare Service Quality and Evaluation: IGI Global: Medical Information science Reference; 2016. p. 141.
Jangra P, Thakral S, Pachar S, Kumar D. Geographic information system (GIS). Int J Sci Eng Comput Technol 2013;3:152.
Mesgari M, Masoomi Z. GIS applications in public health as a decision making support system and it's limitation in Iran. World Appl Sci J 2008;3:73-7.
Burrough PA. Principles of geographical information systems for land resources assessment. Geocarto Int 1986;1:54.
McLeod KS. Our sense of Snow: The myth of John Snow in medical geography. Soc Sci Med 2000;50:923-35.
Alves M, Pozza EA, Machado JC, Araujo DV, Burrough PA, Mcdonnel RA. Geo statistical modeling of spatial distribution of common bean and soybean diseases and its relation to a sole fertility and mineral plant nutrition. Princ Geogr 2008;28:53.
Crampton JW. A history of distributed mapping. Cartogr Perspect 2000;3:48-65.
Cooke DF. Topology and TIGER: The Census Bureau's Contribution. Upper Saddle River, NJ: Prentice Hall; 1998. p. 52-3.
Goodchild MF. Geographic Information System: Springer Us: Encyclopedia of Database Systems; 2009. p. 1231-6.
Maguire DJ. An overview and definition of GIS. Geographical Information Systems: Principles and Applications. Vol. 1. 1991. p. 9-20.
Harinath S, Murthy UN. Spatial distribution mapping for air pollution in industrial areas case study. Ind Control Pollut 2010;26:217-20.
Ketzel M, Berkowicz R, Hvidberg M, Jensen SS, Raaschou-Nielsen O. Evaluation of AirGIS: A GIS-based air pollution and human exposure modelling system. Int J Environ Pollut 2011;47:226-38.
Porter JD. Geographical information systems (GIS) and the tuberculosis DOTS strategy. Trop Med Int Health 1999;4:631-3.
Watson A, Barker S, Ardent K. An initial investigation into the potential link between air pollution and asthma using geographical information system based technique. WIT Trans Ecol Environ 1995;6:447-54.
Brauer M, Hoek G, Van Vliet P, Meliefste K, Fischer PH, Wijga A, et al.
Air pollution from traffic and the development of respiratory infections and asthmatic and allergic symptoms in children. Am J Respir Crit Care Med 2002;166:1092-8.
Briggs DJ, Collins S, Elliott P, Fischer P, Kingham S, Lebret E, et al
. Mapping urban air pollution using GIS: A regression-based approach. Int J Geogr Inf Sci 1997;11:699-718.
Maantay J. Asthma and air pollution in the Bronx: Methodological and data considerations in using GIS for environmental justice and health research. Health Place 2007;13:32-56.
Goodchild M. The Health Geodatabase Model. Progress Report, University of California, Santa Barbara; 2003.
Wen Hsiang W. Generalized Linear Models. Department of Statistics, Tunghai University, Tunghai; 2000.
Keola S, Tokunaga M, Tripathi NK, Wisa W. Spatial Surveillance of Epidemiological Disease: A Case Study in Ayutthaya Province. Thailand: GIS@
World Health Organization. Summit County Water Quality: Septic Systems and Potential Nitrate Pollution Analysis; 2002. Available from: http://www.euro.who.int
ESRI. Enterprise GIS in Health and Social Service Agencies. Environmental Systems Research Institute, Inc. White Paper; 1999.
Andreadis TG, Anderson JF, Vossbrinck CR, Main AJ. Epidemiology of West Nile virus in connecticut: A five-year analysis of mosquito data 1999-2003. Vector Borne Zoonotic Dis 2004;4:360-78.
Centers for Disease Control Prevention. Laboratory-Acquired West Nile Virus Infections-United States, 2002. Vol. 51. MMWR Morbidity and Mortality Weekly Report, 2002. p. 1133.
Hayes EB, O'Leary DR. West Nile virus infection: A pediatric perspective. Pediatrics 2004;113:1375-81.
Iwamoto M, Jernigan DB, Guasch A, Trepka MJ, Blackmore CG, Hellinger WC, et al.
Transmission of West Nile virus from an organ donor to four transplant recipients. N Engl J Med 2003;348:2196-203.
Kusne S, Smilack J. Transmission of West Nile virus by organ transplantation. Liver Transpl 2005;11:239-41.
Rios M, Zhang MJ, Grinev A, Srinivasan K, Daniel S, Wood O, et al.
Monocytes-macrophages are a potential target in human infection with West Nile virus through blood transfusion. Transfusion 2006;46:659-67.
World Health Organization. Public Health Mapping: Inventory of Geographic Information-Draft Document. Public Health Mapping Group, Department of Communicable Diseases, Surveillance and Response, WHO; 2003.
Lai PC, So FM, Chan KW. Spatial Epidemiological Approaches in Disease Mapping and Analysis: CRC Press, Taylor & Francis Group; 2008.
Grover-Kopec E, Kawano M, Klaver RW, Blumenthal B, Ceccato P, Connor SJ. An online operational rainfall-monitoring resource for epidemic malaria early warning systems in Africa. Malar J 2005;4:6.
McLafferty SL. GIS and health care. Annu Rev Public Health 2003;24:25-42.
De Smith MJ, Goodchild MF, Longley P. Geospatial Analysis: A Comprehensive Guide to Principles, Techniques and Software Tools: Troubador Publishing Ltd., Matador; 2007
Shaw NT. Electronic patient records in primary care: Study has serious flaw. Br Med J 2003;327:622.
World Health Organization. The World Health Report 2001: Mental Health: New Understanding, New Hope: World Health Organization; 2001.
Shevale VV, Kalra RD, Shevale VV, Shringarpure MD. Management of oral Sub-Mucous Fibrosis: A review. Indian J Dent Sci 2012;4:107-14.
Statharou A, Papathanasiou I, Gouva M, Masdrakis B, Burke A, Ntaragiannis D, et al
. Investigation of burden in caregivers of the mentally ill. Interdiscip Health Care 2011;3:59-69.
Lionis C. Prevalence of mental disorders in primary health care and the role of the general and family doctor: Experiences from Greece. Psychiatry 2003;1:20-3.
Senate US. United States Dual-use Exports to Iraq and their Impact on the Health of the Persian Gulf War Veterans: Senate Hearing Document; 1994. p. 229-43.
Zhang W, Chen Q, McCubbin H, McCubbin L, Foley S. Predictors of mental and physical health: Individual and neighborhood levels of education, social well-being, and ethnicity. Health Place 2011;17:238-47.
Foley R, Platzer H. Place and provision: Mapping mental health advocacy services in London. Soc Sci Med 2007;64:617-32.
Briggs DJ. Environmental Health Hazard Mapping for Africa. Harare, Zimbabwe: WHO-AFRO; 2000.
Joseph M, Wang F, Wang L. GIS-based assessment of urban environmental quality in Port-au-Prince, Haiti. Habitat Int 2014;41:33-40.
May JM. Medical geography: Its methods and objectives. Geogr Rev 1950;40:9-41.
Hunter JM. The Geography of Health and Disease: Papers from the First Carolina Geographical Symposium. Chapel Hill, NC: University of North Carolina at Chapel Hill, Department of Geography; 1974.
Cromley EK. GIS and disease. Ann Rev Public Health 2003;24:7-24.
DeMers MN. The aspect of GIS design is covered. Fundamentals of Geographic Information Systems. Ch. 15. New York: John Wiley & Sons, Inc.; 2000. p. 498.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]