Application of GIS in health care facilities planning

Spatial Epidemiology
The second area of health care research is known as spatial epidemiology. There are several questions that are commonly asked in spatial epidemiology studies, which include: where are the incidences located? what are the environmental characteristics of these areas?, are there associations between health incidences and the environment at other locations?, and, what patterns are evolving? (Nicol, 1991). GIS is considered as a useful tool for answering the preceding questions. For example, GIS can define the actual location of health events, and then overlay analysis can be used to create new spatial relationships and to tag the various socio-economic and environmental information to the health data.

There are several studies that have applied GIS for these issues. For instant Brown et al, 1991, have used GIS for the mapping of spatial variations in health care provision in Merseyside, Wrigley, 1991, have also used GIS in mapping incidence diseases in relation to population types. Another example of GIS application in epidemiology is called the Health and Environment Geographical Information System (HEGIS), which is being established in Europe by the world health organization (Nicol, 1991). It involves the creation of European wide environment data set, and the aim is to research relationships between health and the environment, to aid policies and management (ibid.). Most of spatial epidemiology studies must be based upon accurate knowledge of the population. Therefore, access to details of population composition and socio-economic characteristics are very necessary for these studies.

Spatial epidemiology studies are concerned with finding good description of spatial incidence of diseases as well as the modeling of such incidence. One way of describing the spatial distribution of a certain disease is by visualizing the GIS choropleth maps that show the spatial distribution of such disease. In such maps, disease rates are plotted over the base map to define the areas that are highly affected from the related disease. Further analysis and modeling of the spatial incidence of diseases can be carried out using for example Kernal or density estimation technique that is used to predicting the spatial variation in diseases risk. (Gatrell and Senior, 1999).

Healthcare Facilities Accessibility and Utilization
This area of health care research concerns with all the issues that are related to the location of the health care facilities. These issues include the optimal location of hospitals and clinics, the relationship between existing locations and health care needs, and the assessment of facilities accessibility. The planning of any health care system should have answers to the following important questions: What are the population needs for health care and how should resources be allocated to the population they are designed to serve? (Gatrell and Senior, 1999).

GIS can assist in finding comprehensive answers for the proceeding questions. For example, Jonhs and Bentham 1995 have used GIS to test for a relationship between health outcomes and accessibility. Forbers and Todd, 1995, have also used GIS to evaluate the potential locations for a new radiotherapy unit for cancer treatment in northwest England.

Finding the best location for a health care facility is considered as one of the health authority task in order to optimize resources. The best location for a facility can be identified using for example location - allocation models that are now been integrated to the modern GIS softwares such as Arcinfo Version 7.

Evaluating the accessibility of existing health facilities is also another task carried by health authorities. Hear the health planners determine the areas, which have poor accessibility for certain, health facility and then prepare proposals for improving such low level of health care accessibility. One way of improving such accessibility is by increasing the capacity of the related health facility, but this can only be achieved after intensive analysis of the area that contain such a facility.

Health Care Planning Data
In order to evaluate the existing location of a health service or to prepare a new site location health care, planners have to collect large set of data that then can be used for the relevant Health care issue. There are several ways of classifying this type of data, but one method is based on the GIS data format types, i.e. dividing the health data into three main groups which are point, area and line data.

In a GIS, point data can be a model for the locations of residences, hospitals or ambulance stations. Each one of the point data can have different attribute information. For examples the locations of individuals might include attributes for the presence or absence of a disease, age, gender, occupation, and so on.

Population zones or census data on the other hand are examples of area data format which can be captured and stored in GIS and can be used for different health care studies. For instance census data can be used to analyze the socioeconomic status of certain patient locations.

Finally, line data such as road network are used in GIS to study the travel journey to and from health facilities locations. They are also used to analyze the routes used by emergency vehicles and to identify how fast do ambulance vehicles reaches to patient locations.

Using GIS in Hospitals Facilities Planning
One area of GIS research in health care planning field is concerns with measuring accessibility to health facilities (Section 2.3). This part will concentrate more on this issue and explain how GIS is used to analyze accessibility to hospitals in Jeddah City, Saudi Arabia. There are three important factors that affect the level of accessibility in any facility location. These are the capacity of the facility, the amount of demand for such facility, and the transportation network that communicate such demand to the relevant capacity. All of these three factors are included in the example of Jeddah hospitals.

The Data Base
In order to build this application, the present study has collected large set of data that are then entered into the GIS to form the database of this application. This means that all of the collected data were in a paper format, i.e. they were not digital. Accordingly, all of the collected data have been entered into the GIS using the digitizing method. The present study has captured three major maps (GIS Coverages) and then added to them their relevant attribute (non-spatial) data. These coverages are the road network, the hospital locations and the population coverage. (Figures 1 and 2). The nonspatial data which are linked to those coverages include the hospitals size (capacity), no of people lives in each district of the city, and the population density of these district. All of these data are then used for the modeling process of hospital accessibility.

The Modeling Process
Once the required data have been captured into the GIS, then the following step was to decide about the relevant analysis methods that may be used for determining hospital accessibility. There are three main GIS spatial analysis functions that could be used for analyzing the accessibility of any selected facility location. The first one is known as buffer analysis which draw buffer around existing facilities proportional to the latter.s size and capacity (Davis, 1996). The second method is related to the GIS network analysis module where population in a network is allocated to the nearest facility locations. Site suitability analysis is the third GIS function that identifies sites according to the suitability for the location of facility under a set of certain (ibid.). Looking at these three GIS functions, the present study has selected the second method that is the network analysis module as the analysis tool for determining hospital accessibility in Jeddah. The main reason for this selection is that hospital demand can be included in the network analysis functions while it is not possible to do so by using buffer or suitability analysis functions. In most GIS softwares, the network analysis module consists of several modeling functions including finding shortest path, service area a model, allocate model, location - allocation model and spatial interaction model. The present study has used the service area model that is one of Arcview (a GIS software produce by ESRI, USA) network analysis functions for evaluating hospital accessibility. This function can find the accessible streets within certain distances of a site and accordingly the streets which are not selected by this function are representing the problem areas i.e. they have poor accessibility (ESRI, 1997).