What is GIS?

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GIS is the abbreviation for Geographic Information Systems. Conventional maps mark the locations of objects as they occur on the Earth's surface. GIS technology takes that concept further to provide a more comprehensive description of an area.

Geographic Information Systems are computer-based data storage tools that capture object location in the same context as object attribute information.

Maps are used to represent both real and imaginary objects in relation to a larger surrounding area. Streets and rivers are a couple of examples of real objects, while property boundaries and addresses are considered imaginary. That is not to say that they are invalid measurements, but rather they are not represented by a physical object in the real world. There is no line on the ground that marks property boundaries, but there is a river running along the surface.

GIS technology can capture the locations of these real and imaginary objects and store that information in a database. Each object (street segment, stream, etc.) is stored in a separate row, in a table structure. The table structure is designed to hold rows that are divided into one or more columns. If you are familiar with spreadsheet applications, a table structure is similar to that of a spreadsheet file. In each table row, location information is stored in a single column. The table can store other information about each object by adding new columns. This information describes each object in a quantitative or qualitative way.

For example, consider a table containing information about street segments. Each segment would have a start and end point, and possibly several points in between where the segment changes direction. That's one column. Then, maybe another column contains the length of that segment, in miles. That's a quantitative description of the line segment. Or, maybe the name of the street is stored in another column. That is an example of a qualitative characteristic.

After this information is gathered and stored, it can be displayed on a map and printed, or viewed on the internet in a web browser.

However, a geographic information system is more than just data storage. In addition to the data collection and storage, GIS technology includes necessary hardware (computers) and software that is used to create, view, and analyze the data. Beyond displaying the data in a map, on paper or electronically, GIS software is used to create, edit, and analyze location-based information. The software is designed to allow users to easily compare the attributes of stored objects to identify trends or patterns, in order to recognize more general characteristics of an area. This kind of analysis can be used to study naturally occurring phenomena, or in support of decisions regarding resource distribution or consumption. The potential for applying this technology is practically endless.

For more information about Geographic Information Systems, visit our Additional Links page. This page contains links to other web sites that offer further explanation and examples of GIS technology.

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