2.1. Definition

Geographical Information Systems (GIS) are computer systems based on hardware, software, and georeferenced data that can be used to collect, store, manage, process, analyse, and visualize both spatial and non-spatial information representing real-world geographic phenomena (Burrough and McDonnell, 1998; Neteler and Mitasova, 2008). Georeferenced data refers to any data that are linked to a location on the Earth’s surface through the use of a geographic or projected coordinate system. GIS data are digital objects which represent real-world entities (Longley et al., 1999) and are defined by: their geometric properties (spatial location), their attributes (characteristics associated with each object), and their topology (definition of how entities are related to others in space) (Burrough and McDonnell, 1998). In other words, data provide means to locate them in space and can be overlaid, calculated, manipulated, visualised and analysed along with other data layers that use the same coordinate system. Each entity in the real world is represented by a data layer with geometric and topologic properties and an associated set of attributes, in the form of a table, which define the characteristics of that entity. GIS facilitates the analysis of spatial relationships within datasets based on the topological properties within the data. Topology refers to the interconnectivity and interrelated properties between data and defines and describes how spatial objects relate to their neighbours in space. This geographic descriptor is what sets GIS data apart from other data types (Burrough and McDonnell, 1998) (for a list of free GIS books and other information sources see Table 1).

Table 1. Publication names, authors, and websites of free GIS Books and information sources.

Name of publication

Author(s), year


Map Projections: A Working Manual

Snyder, 1987


Geospatial Analysis - A comprehensive guide

De Smith, Goodchild, and Longley, 2007


A Practical Guide to Geostatistical Mapping

Hengl, 2009


GIS Commons: An Introductory Textbook on Geographic Information Systems

Schmandt, 2009


Various ESRI E-books