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A Geographic Information System (GIS) is a technology that puts a vast amount of data we gather on our computers into a
format that is much more comprehensible by the average person. A GIS is a planning and decision making tool that has been
called intelligent mapping. How does a GIS give mapping its intelligence? Let's take a look.
In a GIS each unique piece of mappable information is kept in its own place on the computer. In GIS terminology, this unique piece of mappable information is referred to as a layer. In Wilson we have hundreds of layers of information. Some of these layers are as follows (see diagram below): City Limit Boundaries, Planning Zones, Water Lines, Crime, Tax Parcels, and Recreation Sites. All cartographic information is contained in these layers. However, if we had only the cartographic information then we would have a Computer Aided Drafting and Design (CADD) system. GIS allows for the powerful addition of tabular information to be attached to the GIS layers.
 Each element of a map layer is given a unique ID number. These unique ID numbers tie into a database management system. This allows for the addition of attributes describing the cartographic data. For example, Wilson has a tax parcel layer that contains cartographic information depicting the boundaries of each parcel in the county and for each parcel there are approximately 75 attributes describing the parcel. This allows a user to be able to sit at a GIS terminal, visually select an area of interest, bring any layers of interest onto the screen, and select and list information about any of these layers.
As helpful as the mapping and data query functions of a GIS are, these are not what sets it apart from other computer
systems. A GIS has the ability to perform sophisticated analyses not possible on any other type of system. Many GIS projects
require information from more than one GIS layer. A project may require that information from four or five layers be
combined to give an answer to a particular issue. Multiple layers can be combined to yield a new layer with the desired
information. For example, one might be looking for an optimal site to locate a new electric substation. Pertinent layers
are combined and the most suitable combination of these layers can be found. The GIS system then displays one map showing
all of the needed information in one easy to reference place.
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