Week 1: What is GIS?
ENV208/ENV508 – Applied GIS
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WHAT IS GIS?
A GIS integrates hardware, software, and data for capturing,
managing, analyzing, and displaying all forms of
geographically referenced information.
GIS allows us to view, understand, question, interpret, and
visualize data in many ways that reveal relationships,
patterns, and trends in the form of maps, globes, reports, and
charts.
A GIS helps you answer questions and solve problems by
looking at your data in a way that is quickly understood and
easily shared.
http://www.youtube.com/watch?v=-ZFmAAHBfOU
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WHAT IS GIS?
G = Geographic
• Implies that data items have known spatial locations
on the Earth’s surface (or they can be calculated)
– Spatial vs. aspatial data
• Relative location (where things are in relation to
everything else)
• Geography theory and techniques form the basis of
GIS
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WHAT IS GIS?
I = Information
• Data are organised to generate knowledge
• Factual and interpretative
• Output: maps, images, graphs, tables, analysis
results…
• Information technology (e.g. computer systems)
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WHAT IS GIS?
S = Systems (Science, Studies, Services..)
• Made up of several inter-related and linked
components/subsystems
• Capable of data:
– Capture
– Storage
– Input
– Manipulation and transformation
– Visualisation, query, and analysis
– Output 5
WHAT IS GIS?
Simplest definition – three components
1. Database (table of information)
2. Spatial data (geographic information)
3. Links between the two
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WHAT IS GIS?
1. Database (table of information)
Total population
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WHAT IS GIS?
2. Spatial data (geographic information)
State/Territory
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WHAT IS GIS?
3. Links between the two
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WHAT IS GIS?
GIS organises the data into a map, and also facilitates much
more.. By using a data layer approach
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Geographic data are linked to attribute data in Geographic
information Systems
WHAT IS GIS?
WHAT IS GIS?
Core of GIS = Layers
• Each layer is brought together
based on spatial data.
• It’s the bringing together of all of
this data, and being able to see the
relationships between these data,
that makes GIS such a powerful
tool.
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WHAT IS GIS?
• The data can be related to
anything… roads, hospitals,
houses in an urban setting; or
forest patches, water bodies,
animal nests.
• Once in a GIS, all of the data can
be investigated to test the
relationship between different
parameters because they are
linked spatially.
• Aspatial data is of limited value
until they can be attributed to a
location
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WHAT IS GIS?
Data layers must be
aligned with one another
Needs a referencing
system
More on datum's and
map projections later in
the unit..
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Vector • Points, lines and polygons e.g.
topographic maps
• Discrete geographic features
• Shapefile, KML, GML, GPX…
Raster • Grid cells or pixels e.g. satellite images
• Continuous geographic features
• GeoTIFF, JPEG2000, HDF5, IMG, NetCDF, Esri GRID…
TWO MAIN DATA STRUCTURE TYPES
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X
Point
(City location)
Line
(Road)
Polygon
(Fire extent)
x
Node Vertex
TWO MAIN DATA STRUCTURE TYPES
Vector
– a graphic data structure represented by points, lines and polygons using exact x, y coordinates.
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Industrial
Vegetation
Lake
Residential
TWO MAIN DATA STRUCTURE TYPES
Raster
– A regular grid of cells covering an area
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2 main types of data structure
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WHAT GOES IN AND COMES OUT
OF A GIS?
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COMMON INPUT DATA FOR GIS
• topographic
• cadastre
• geology
• hydrology
• land cover/vegetation
• soils
• elevation
• census data
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Geographic data:
– Topographic maps
– Satellite and airborne scanner images & photos
– Administrative boundaries
– Statistical data on people, land cover & use
– Data from marketing surveys
– Data on utilities
– Data on land form, water, biological activity,
natural hazards & disasters
COMMON INPUT DATA FOR GIS
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COMMON INPUT DATA FOR GIS
Remotely sensed imagery and products can be very useful
WHERE CAN YOU GET INPUT DATA
FROM?
• National mapping agencies
• Local government
• Military
• Remote sensing companies and satellite
agencies
• National resource surveys
• Scientists
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COMMON OUTPUT FROM GIS
• maps
• tables
• charts
• statistics
• reports
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WHY USE GIS?
• To explore relationships between features
distributed unevenly over space
• To seek out patterns that may or may not be
apparent without using the query, selection,
analysis and display functions
• Make maps to communicate
information
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WHY USE GIS?
• faster and easier than manual methods
– labour saving
• can handle large volumes of data
• have spatial and temporal analysis capabilities
• useful decision making tools
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WHY USE GIS?
Examples of questions that can be answered using GIS
• Does it make sense to put a shopping centre here?
• Do we expand the existing airport here or build a new one over there?
• Which pockets of endangered wildlife should we protect?
• What is the impact of waste facilities on local health patterns?
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GROUP ACTIVITY
• How might GIS be used?
• What spatial questions might be asked?
• What kind of data might be needed?
• What would the output be?
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WHERE GIS IS BEING USED
• Business
• Marketing
• Public Safety
• Disaster Response
• Medical Services
• Utilities
• Military
• Transport
• Local Government
• Environment
http://www.youtube.com/watch?v=4M0q9INPYHc
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• Professionals in every field are becoming
increasingly aware of the advantages of using GIS
WHERE GIS IS BEING USED
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• As a GIS analyst, GIS programmer.. A position that is
explicitly GIS
• As a biologist, ecologist, real estate professional where
GIS is a fundamental tool and a way of thinking
WHERE GIS IS BEING USED
GIS IN CONSERVATION
• Where a species is
• Where a species could be
• Helps identify distribution information
• Helps identify locations of high biodiversity importance
– guide decisions about policy and action needed to protect these areas and species
• Allows businesses and researchers access to biodiversity information to guide decisions
• http://www.iucnredlist.org
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Relevance of GIS to society
• Name some areas of concern in your community,
region, country, world
– Energy, sustainable agriculture, natural hazards,
epidemics, biodiversity, transportation, water
quality, climate change, migration and
urbanisation
• All of the key issues have a geographic component and
therefore can be better understood and solved using
GIS
SPATIAL QUESTIONS
Law enforcement:
Where in the city are the majority of the drug arrests made? Where do most of the violent crimes occur? Is there a spatial relationship between these two variables?
Realtor:
What is the average price of homes in this neighbourhood relative to those in nearby neighbourhoods?
University admissions administrator:
Where do most of the student applicants live? Where are the economically disadvantaged areas? How can we attract more applicants from these areas?
Aid worker:
Where is the area of greatest human suffering and greatest poverty damage? How can we maximise the impact of our relief efforts?
Delivery truck driver:
What is the most efficient route for my 25 deliveries today?
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What GIS can do…
• GIS allows you to bring together many types of data
together based on geographic location of the data
• Can integrate, visualise, manage, question, interpret
and present this information using GIS
• Allows you to identify relationships in your data
SUMMARY
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SUMMARY
• GIS has the power to
– create maps
– integrate information
– visualise scenarios
– solve complicated problems
– present ideas
– develop effective solutions
• To use GIS effectively need to learn to think spatially, know the correct procedures for analysing your data and how to communicate your findings
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COMING UP…
Practical session 1
• Test login
• Start ESRI Virtual Campus module 1
• Use the time to ensure personal computers are
running ArcGIS properly
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COMING UP..
• Week 2:
– Making maps, data visualisation and other GIS
outputs
– Module 2: Creating Map Symbology
• Week3:
– Coordinates and Projection systems
– Module 3: Referencing Data to Real Locations
– Module 4: Organizing Geographic Data
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• This course requires a lot of computing work but assumes no
previous computing knowledge
• Learning curve for computing laboratories
Week 4
Week 3
Week 2
Time
Kn
ow
led
ge
Words of encouragement..
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