The network of polygons created by such zones is called Vornoi diagram . Search based on overlay - object based operations where the overlaying of features is used as a base for search and selection. Interpolation and surface modelling - GIS techniques used in assigning spatial and attribute information to unknown locations based on known locations. These techniques utilize various statistical and mathematical formulas to interpolate data over the entire area of interest. These techniques are extensively used in raster and network data models.
Epidemiology is one of the fields that applies such tools extensively.
Geographical display and interactions - most of today's GIS software packages offer some graphic and cartographic tools that allow for producing of fairly high visual outputs. Some of these packages include 3D applications, projection transfers, graphs, cartograms and other visual components. In most cases GIS software can be customized using simple functions. The latest trends in GIS include on-line Internet mapping tools.