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Lecture 20
Spatial Decision Support
Systems (SDSS)
Outline:
– Introduction
– Principles and theory
– Examples
– Online SDSS
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Introduction
• The ultimate application? OR... is this where the
previous 9 (or 19) lectures have been leading?
• Use of GIS for environmental applications
includes:
1. data management
2. characterisation and assessment
3. modelling and spatial analysis
4. management and decision support
• Applications 1 thru 3 culminate in 4... the end use?
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Application or decision
support?
• An application may end at any point
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CORINE, GRID, GEMS, etc. end at 1
descriptive/mapping exercise and EA may end at 2
predictive modelling exercise may end at 3
BUT they must all start at 1 and work through these
stages in sequence
• The ultimate end application must be decision
making (i.e. management) and use in support of
decisions made
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Aims of EnvSci
• Aims of environmental science:
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to accumulate knowledge pertaining to the
environment?
to understand environmental processes and linkages?
• Objectives of environmental science:
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gather data pertaining to environmental phenomena and
processes via empirical investigation?
to develop theories encompassing environmental
themes?
i.e. to gain understanding and insight through study
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Aims of EnvMan
• Aims of environmental management:
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to prevent environmental deterioration and
degradation?
to promote sustainable use of the environment?
to prevent over use or exploitation of natural resources?
to preserve environmental diversity?
• Objectives of environmental management:
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to control the environment and/or our influences upon
the environment via direct or indirect action?
i.e. putting environmental science to work!
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Decision making or support?
• Decision making vs decision support
–
GIS can provide certain tools for assisting in
the decision making process
 i.e.maps/displays
as means of visualising the
problem
 overlays as means of defining relationships
 modelling as means of predicting outcomes
 etc
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…the answer
• GIS functions on their own are NOT
decision making tools...
– (i.e. they only ASSIST in the decision making
process)
– ...therefore, GIS is not a decision making tool,
it is a decision SUPPORT tool
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Decision making
• Decision making:
–
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a decision is a choice between alternatives to
meet specific objectives
the alternatives may represent:
 different
courses of action
 different hypotheses
 different use of a geographical entity
 etc.
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Decision objectives
• Objectives are governed by management goals and
in turn determine the range of alternatives
–
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e.g. identify areas of high risk in soil erosion example
in order to address the goal of preventing soil erosion
resulting alternatives may be different maps
representing different management plans
• Process governing the way decisions between
alternatives are made is the “decision rule”
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Conflict!
Making decisions to meet specific objectives
often involves CONFLICT
Solving these conflicts is the art of good
decision making
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Why GIS is not decision
making
• GIS is not a decision making tool kit
–
to make (good) decisions requires:
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knowledge & foresight
insight & intelligence
expertise, etc.
i.e. rational choice between alternatives (especially
where conflicts are present)
GIS does not provide the above, BUT it can fulfil
important role in decision making by providing
decision support
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Decision support is…
• Decision support:
–
–
role of aiding the decision making process
simplest level:
 expert
advice regarding a decision between
alternatives
–
most complex level:
 dedicated
computer systems
 i.e. decision support systems (DSS)
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Definition of a DSS
• In general terms, DSS are:
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computer-based systems
dedicated to a restricted but well defined area of
application
systems incorporating modelling and analysis with data
and database management systems
systems which do not make decisions, but facilitate
logistics of decision making process
interactive systems that help decision maker
systematise decision making process
providers of custom-built information
providers of user-friendly GUI with short response
times
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Developing Spatial DSS
• The role of GIS?
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GIS is an INCREDIBLY USEFUL tool
GIS toolbox can be used to develop SDSS
SDSS retain the general characteristics of basic DSS
but in addition they include:
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spatial data input capabilities
storage of complex structures common in spatial data
analytical techniques unique to spatial data
cartographic output
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Basic SDSS structure
Models
G.I.S
Database
User Interface
User: expert
knowledge
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GIS as SDSS?
• GIS fits nicely with additional requirements of a
SDSS, but still does not meet the overall
requirements of a DSS
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GIS do not include expert knowledge
GIS do not possess artificial intelligence (AI)
GIS have only limited spatial analysis functionality
GIS are not very user friendly
GIS are not dedicated systems
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Question…
• How can we address these short-comings of
GIS in developing SDSS?
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Example: nuclear waste
disposal
• Example of a facilities location exercise involving
multiple and conflicting criteria
–
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ideal example application for a SDSS from initial site
survey through to public inquiry
problem has been approached by NIREX since 1981
and they are now on their fifth attempt
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four previous failures due to poor information, poor public
communication, obsession with engineering issues, etc.
why didn't they listen to me?
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Nuclear waste… the problem
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Nuclear waste disposal… how?
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A GIS approach…
•
Basic GIS/MCE site search:
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identify screening (constraint) factors and their
threshold criteria and use map overlay to identify areas
satisfying above constraints
identify multiple site-based factors on which to
optimise
establish weighting scheme for factors
run MCE routine to identify optimal or near-optimal
sites
run sensitivity analyses and identify final sites
–
pass the buck!
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Advantages…
•
Advantages of such an approach are:
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good at deterministic area screening
provides an application framework for
MCE
MCE provides GIS with spatial analysis
functionality
provides a rational and objective
approach
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Nuclear waste disposal… where?
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Role of SDSS
•
SDSS may be used throughout the site
selection decision making process as
follows:
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aiding initial decision making process
public information, consultation and
participation
decision support at public inquiry
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Online SDSS
• If public participation is goal then need to:
– maximise access to data and tools
– maximise scope for public participation
 at
all stages of planning process
 at all stages of decision process
• Utilise web-based GIS for SDSS
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Examples web-based SDSS
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Virtual Slaithwaite
WOODS
Nuclear waste siting
Wilderness mapping
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Conclusions
• SDSS is utlimate end application of
environmental GIS
– development of GIS-based SDSS
– online SDSS
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Practical
• Running online SDSS
– Run the eMapScholar online GIS exercise
– http://www.ccg.leeds.ac.uk/teaching/nuclearwaste/
– You must:
 Complete
the full exercise
 Fill in the profile form
 Fill in the feedback form
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