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- A fast computer, large data storage capacities, and a high-quality, large display form the hardware foundation of most GIS.

- provides the tools to manage, analyze, and effectively display and disseminate spatial information. GIS’ tools will view and edit these data, manipulate them to generate and extract the information we require, and produce the materials to communicate the information we have developed.

is designed to provide a large set of geoprocessing procedures, from data entry through analysis to most forms of data output. It supports multiple data formats, many data types and structures, and literally thousands of possible operations that may be applied to spatial data.

is an open-source software project, an initiative under the Open Source Geospatial Foundation. The software is a collaborative effort by a community of developers and users. It is free, stable, changes smoothly through time, with the source code available so that it can be extended as needed for specific tasks.

provides a substantial set of spatial data analysis capability. Data may be entered, verified, and output. Data may also be searched for features with particular conditions or characteristics. More sophisticated spatial analysis may be performed, including path finding or data combination.

- is a free, opensource GIS that runs on many platforms. The system was originally developed by the U.S. Army Construction Engineering Laboratory (CERL), starting in the early 1980s, when much GIS software was limited in access and applications.

Data in a GIS represent a simplified view of physical entities, the roads, mountains, accident locations, or other features we wish to identify. Each entity is represented by a spatial feature or cartographic object in the GIS, and so there is an entity–object correspondence.

Attributes are often presented in tables and arranged in rows and columns. Each row corresponds to a spatial object, and each column corresponds to an attribute. Attributes may be in many forms, but all attributes can be categorized as nominal, ordinal, or interval/ratio attributes.

variables that provide descriptive information about an object. Example is the color in the 3rd column.

imply a ranking or order by their values. An ordinal attribute may be descriptive, such as high, mid, or low, or it may be numeric; for example, an erosion class may be given a value from 1 to 10.