Introduction to the course
January 9, 2012
Points to Cover
What is GIS?
 GIS and Geographic Information Science
 Components of GIS

 Spatial data
Defining GIS
Many definitions exist
 Three main points:

 GIS is a computer system consisting of hardware and
software
 GIS works with spatially referenced data
 GIS carries out various management and analysis
tasks on these data

GIS is much more than a graphic package or a
mapping system
 Turn raw data into information
GIS and Geographic Information
Science

Geographic Information Science refers to the
body of knowledge underpinning GIS
 Draws and synthesizes knowledge and methods
created by other disciplines
 Involves research into:
 Fundamental issues arising from the creation, handling,
storage and use of geographic information (Longley et
al., 2005)
 Impacts of GIS on individuals and society and the
influences of society on GIS (Goodchild, 1997)
Components of a GIS
Various points of view exist
 More comprehensive
definitions include:

 Computer system
○ Hardware and operating system
 Software
 Spatial data
 Data management and analysis
procedures
 Organizational environment
Computer System
GIS run on a variety of computer systems
 Essential elements of the hardware (Burrough,
1986)

 Processor with sufficient power
 Sufficient RAM
 Good quality graphic interface, including a good
videocard
 Data input and output devices
Software

GIS software includes the following basic
modules:
 Data input and verification
 Data storage and database management
 Data output
 Data transformation tools
 Data analysis and manipulation tools
Spatial Data: Concept of Data

Data are observations from monitoring the real
world
 Hourly temperature readings at the Regina airport
 Total number of new social assistance recipients per
month

Raw numbers

Data taken by itself is relatively useless for
making decisions
Spatial Data: Data and Information

Data are
→ Processing
& Display
→ Information
Data
observations
from monitoring
the

Data processing may include
 Summary/aggregation
 Analysis
 Adding context such as subject, scale or unit of
measurement

Metadata
 Information that describes the content, quality, condition,
origin, and other characteristics of data or other pieces of
information.

Communication is an important step in converting
data into information
Spatial Data: Dimensions of Data

Data has three dimension (modes)
 Temporal: provides a record of when the data were
collected
 Thematic: ties the data to the real world feature or
event
 Spatial: references the location of the features

The data can be classified based on the
dimension that is used to organize it
 Thematic data: data organized by theme
Spatial data: Structure

Ways of structuring data in a GIS
 Layer-based approach:
 Layers containing data related to the
same theme or on the same type of
features
 Defined extent
 Object-oriented approach:
 Spatial entities are regarded as discrete
objects with empty spaces between
them
Spatial data: Structure

ArcGIS software uses the layer-based approach
to structuring spatial data
 Layers can be stored as collection of interrelated files
 Coverages
 Shapefiles
 Layers can be stored as a feature class in a
geodatabase
 The geodatabase storage model is based on a series of
relational database concepts
 The multitier architecture of the geodatabase is
sometimes referred to as an object-relational model
(ArcGIS Help files, ESRI ,1995-2010).
Data management and analysis

GIS handles two types of data
 Spatial data
 Gets visualized in the graphic interface as map
features
 Non-spatial attribute data
 Provide information about features

Functions performed by GIS
 Data input, management and output
 Data transformation and analysis
 Transformation is a process of changing how the
data are represented
Data management and analysis

GIS handles two types of data
 Spatial data
 Gets visualized in the graphic interface as map
features
 Non-spatial attribute data
 Provide information about features

Functions performed by GIS
 Data input, management and output
 Data transformation and analysis
Organizational Environment

GIS utilization ranges
 From small research projects carried out be a
single person
 To large-scale corporate distributed systems
designed and used by different groups of users

Introducing GIS into an organization brings
changes to all aspects of business
 Successful implementation of GIS requires taking
into account existing needs and available
resources