Introduction to GIS

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Introduction to GIS
Module 1

• Noriel Christopher C. Tiglao, Dr. Eng
• 24 January 4 February 2005
• Statistical Research and Training Center (SRTC)
• Quezon City, Metro Manila

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Presentation Outline

• Definitions of GIS
• The Feature Model
• Capabilities of GIS
• Key Activities in a GIS
• Brief History of GIS
• Components of GIS
• Data Models
• GIS Applications

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Definitions of GIS

• Different definitions have evolved over the years
• Development of new technologies
• All GIS definitions recognize that spatial data
  are unique because they are linked to maps (Space
  matters!)

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Definitions of GIS (contd.)

• A GIS at least consists of a database, map
  information, and a computer-based link between
  them

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Definitions of GIS (contd.)

• Definition 1 A GIS is a Toolbox
• A powerful set of tools for storing and
  retrieving, transforming and displaying spatial
  data from the real world for a particular set of
  purposes

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Definitions of GIS (contd.)

• Definition 2 A GIS is an Information System
• A special case of information system where the
  database consists of observations on spatially
  distributed features, activities or events, which
  are definable in space as points, lines or areas
  (i.e. feature model)
• GIS manipulates data about these points, lines,
  and areas to retrieve data for ad hoc queries and
  analyses

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The Feature Model

• Divides a mapped landscape into features, that
  can be points, lines, or areas
• Using a GIS involves capturing the spatial
  distribution of features by measurements of the
  world or of maps
• Almost all human activity and natural phenomena
  are spatially distributed, and so can be studied
  in GIS
• A GIS uses map features to manage data

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Features
Point
Line
Area
R i v e r
Fire Hydrant
L a k e
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Definitions of GIS (contd.)

• Definition 3 A GIS is an Approach to Science
• Understanding the potential capabilities of GIS
• Research on GIS and with GIS
• Geographic Information Science

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Definitions of GIS (contd.)

• Definition 4 A GIS Plays a Role in Society
• Changing the way people live and work
• Measurement and representation of geographic
  phenomena and interacts with social structures
• Public Participation GIS (PPGIS)
• GIS for decision-making

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So, what is a GIS?

• A GIS uses geographically referenced data as well
  as non-spatial data and includes operations which
  support spatial analysis
• Data processing system
• GIS is a type of information system applied to
  geographical data
• Socio-technical role

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GIS in the Planning Process
Data Collection
Take Action
Real World
Data Sources
Input of Data
Users
Data Management
Analysis
Information for Decision Making
Data Retrieval and Analysis
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Capabilities of GIS

• Data Input
• Converts existing data into GIS format
• Common sources of data include papers maps,
  tables of attributes, aerial photos, and
  satellite imageries
• A major bottleneck in the implementation of GIS

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Capabilities of GIS (contd.)

• Data Management
• Functions needed to store and retrieve data from
  the data base
• Representation of geographic information
  (geo-information) into suitable format for
  efficient processing
• Organizational structures needed to support GIS
  (procedures, processes, human organization)

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Capabilities of GIS (contd.)

• Data Manipulation and Analysis
• Components that are capable for data exploration
  and analysis

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Capabilities of GIS (contd.)

• Data Output
• Presentation of outputs by maps and visualization
  tools (e.g. 3-D, animation)

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Key Activities/ Tasks in a GIS
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GIS Processing Flow
Visualization
Storage/
Management
Representation
Query
Reality
Acquisition/
(Geo-objects)
Update

Existing maps
Spatial Analysis
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Brief History of GIS

• Major events that shaped GIS
• Era of Innovation (1950s to 1970s)
• Era of Commercialization (1980s to 1990s)
• Era of Exploitation (21st century)
• (based on Longley et al., 2001 pp. 12 to 13 and
  Foresman, 1998)

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Brief History of GIS (contd.)
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Brief History of GIS (contd.)
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Brief History of GIS (contd.)
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Components of GIS

• GIS Hardware
• GIS Software
• GIS Data
• GIS Methods
• GIS People

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Components of GIS (contd.)

• GIS Hardware

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Components of GIS (contd.)

• GIS Software

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Components of GIS (contd.)

• GIS Data

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Components of GIS (contd.)

• GIS Methods

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Spatial Analysis Methods

• Analysis and manipulation of attribute data
• Transform
• Aggregation
• Overlay, etc.
• Spatial analysis
• Buffering
• Neighborhood analysis
• Network analysis
• Spatial statistical analysis, etc.
• Spatial interpolation
• Point-based data, Areal or volume data
• Computation of measures
• Geometric (coordinate) transformation

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Data Models

• Vector Data
• Uses the feature model
• Geo-objects are represented as points, lines
  (arcs or edges) or polygons (areas)
• Raster Data
• Store information on a lattice or grids

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Raster Data vs. Vector Data
Building Name, Use
Land Owner
Attribute
Road Name, Width, Traffic volume
data
Geo-objects
Tree Species, Age, Height
Water supply (edge)
Water supply Diameter, pressure
Road (polygon)
(Geo-information)
Vector form representation
(Point, Edge, Polygon)
more appropriate for geo-
(Reality)
Building (polygon)
objects with well defined
boundaries
Tree (point)
(such as buildings, man-
Land (polygon)
made objects)
Raster form representation
(Grid form)
representing space
as well as time
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GIS Applications

• Natural Resource GIS
• Faults
• Elevation
• Slope-aspect
• Streams
• Wells/gauging stations
• Ownership/administrative
• Transportation lines
• Settlements/points of interest

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GIS Applications (contd.)

• Urban GIS
• Parcel/land records
• Street network
• Facilities networks
• Districts
• Topography
• Buildings
• Terrain (polygons)
• Terrain (line and points)

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GIS Applications (contd.)

• Urban GIS
• Parcel/land records
• Street network
• Facilities networks
• Districts
• Topography
• Buildings
• Terrain (polygons)
• Terrain (line and points)

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End