GIS for public health management GIS Overview The GIS is a powerful tool for handling spatial data. In the GIS, data is maintained in a digital format. As such the data is in a form more physically compact than that of paper-maps, tabulation, or other conventional formats of presenting information. Large quantities of data can also be maintained and retrieved at greater speeds and at lower cost per unit, when the computer based system is used. The ability to manipulate, integrate and analyse the spatial data and its corresponding attributes at high speed is unmatched by any manual methods. The spatial analysis capabilities of the computer-based GIS distinguishes it from related graphics oriented systems like computer-aided design and drafting. The analysis of complex, multi-spatial and non-spatial data sets in an integrated manner, which forms a major part of the GIS enables georeferenced information to be created and used in a completely different context than before.GIS technology and GIS facility can change the objectives that an organization can attain, but it is the organization that must define what those objectives should be. The Health model encompasses the GIS technology, with capabilities to assist the users in spatial planning.  Fig. 2.1 Main Menu GIS Models and Integration Two approaches or models have been widely used for achieving the linkage between the spatial and attribute information using GIS, namely, the cartography map model and the geo-relational model (Aronson 1987; Healey 1991). In the cartographic map model, information integration proceeds by combining attribute values for cells that lie above or below one another in a stack of superposed layers. The gridcell model is a relatively simple approach to data integration both conceptually and operationally and it has been popular since the earliest days of GIS development.  In the geo-relational model, spatial entities are usually linked with their associated attribute data by means of a common spatial key. Different sets of attribute information are stored in different attribute tables and the relevant information for a given set of spatial feature is accumulated by relating ( or joining) two or more tables of information.  |