Pub. date: 2008 | Online Pub. Date: November 27, 2007 | DOI: 10.4135/9781412953948 | Print ISBN: 9781412928168 | Online ISBN: 9781412953948| Publisher:SAGE Publications, Inc.About this encyclopedia
Geographical and Spatial Analysis
All events have space and time coordinates attached to them—they happen somewhere at some time. In many areas of epidemiology, recording the place of individual events and exposure is vitally important. The recent surge in the availability of desktop computing power, geographical information systems (GIS) software, and interest in the effect of neighborhood conditions on development of disease have caused a resurgence of interest in spatial data analysis. Spatial data consist of measurements or observations taken at specific locations or within specific spatial areas. In addition to values for various attributes of interest, spatial data sets also include the locations or relative positions of the data values. There are three main types of spatial data. The first type of data, geostatistical data, is measurements taken at fixed locations. In most cases, the locations are spatially continuous, that is, data locations are available in close proximity to each other. An example ...