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 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 Data → Processing & Display → 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, ).

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