Transcript Part 4 - Berry and Associates Spatial Information Systems

GIS Modeling
Classes of Map Analysis Operations
GIS Modeling logically sequences map analysis operations
(Spatial Analysis, Surface Modeling and Spatial Data Mining)
to solve spatial problems…
Thinking with Maps
(Berry)
Decision Support Systems Framework
Three elements of a GIS Model
(Berry)
Suitability Modeling (Full Exercise #8)
Relative Suitability
Mountain Property Development
(Berry)
Capturing Model Logic (Command Script)
The logical sequence of map analysis operations is contained in a Command Script
that can be easily changed to simulate different scenarios
(Berry)
Suitability Modeling (Comparing Scenarios)
(Berry)
Transmission Line Siting Model
Existing Powerline
Goal – identify the best route for an electric
transmission line that considers various criteria
for minimizing adverse impacts.
Proposed
Substation
Houses
Criteria – the transmission line route should…
 Avoid areas of high
Roads
housing density
Sensitive Areas
 Avoid areas that are far from
roads
Elevation
 Avoid areas within
or near sensitive areas
 Avoid areas of high visual
exposure to houses
Houses
(Berry)
Siting Model Flowchart
(Model Logic)
Model logic is captured in a flowchart where the boxes represent
maps and lines identify processing steps leading to a spatial solution
Avoid areas of…
High Housing
Density
Far from Roads
In or Near
Sensitive Areas
High Visual
Exposure
…build on this
single factor
(Berry)
Siting Model Flowchart
(Model Logic)
Model logic is captured in a flowchart where the boxes represent
maps and lines identify processing steps leading to a spatial solution
Step 1
Identify overall
Discrete Preference
(1 good to 9 bad rating)
Start
End
Step 2
Generate an
Accumulated
Preference surface
from the starting
location to
everywhere
Start
End
Step 3
Step 2
Step 1
Step 3
Identify the Most
Preferred Route
from the end
location
(Berry)
Step 1
Discrete Preference Map
Calibration
Weighting
HDensity
RProximity
SAreas
VExposure
(Berry)
Step 2
Accumulated Preference Map
Splash Algorithm – like tossing a stick into a pond with waves emanating out
and accumulating costs as the wave front moves
(Berry)
Step 3
Most Preferred Route
…steepest downhill path “re-traces” the accumulated cost wave front that got there first
(Berry)
Generating Optimal Path Corridors
(Berry)
Power and Pipeline Routing (Advanced GIS Models)
…see Application Paper \GW04_routing
Infusing stakeholder perspectives into
Calibration and Weighting
…of Engineering considerations, Natural
Environment consequences and Built
Environment impacts
Global routing solution
identifies the Optimal
Route (blue line) and
Optimal Corridor
(cross-hatched)
…see Application Paper \GITA_Oil&Gas_04
(Berry)
Real World Routing Application (Processing Schematic)
5) The best route and corridor is
determined for conditions
favoring each group’s
perspective and one where all
are equally weighted–
B E N (avg)
1) Locations that
prohibit siting
are eliminated
from
consideration
BEN
BEN
Simulations
BEN
Four alternative routes reflecting
different perspectives
Stakeholder
Groups
Built
Exclusions
Engr.
4) Relative importance weights
for the Criteria Maps within
each group are used to
calculate an overall
preference map
Weighting
Calibration
Natural
3) The categories on each
Criteria Map are calibrated to
a range of 1=best to 9= worst
for siting a transmission line
Criteria
etc.
etc.
Proximity
Buildings
Building
Density
Visual
Exposure
Proximity
Schools
Categories
Excluded
Existing
Utilities
Transporation
Land
Cover
Proximity
Excluded
etc.
Floodplane
Slope
Hydrography
Public
Lands
2) Information that influence transmission line siting are identified
(Berry)
Identifying the Routing Decision Space
Combining alternative corridors identifies the
decision space reflecting various perspectives
E=1 N=1 B=5
E=5 N=1 B=1
E=1 N=5 B=1
E=1 N=1 B=1
Weighting one stakeholder group over the
others derives Alternative Corridors that
emphasize stakeholder particular concerns
…the routing decision space is
identified by combining the
Alternative Corridors
GeoWorld magazine feature article on the EPRI_GTC project http://www.geoplace.com/gw/2004/0404/0404pwr.asp
Acquire Additional Detailed Field Data
The Siting Team
collects additional
very detailed field
data within the
decision space
defined by the
Alternative Corridors
Investigating the Alternative Routes (GIS-derived )
“Simple” Discrete Preference
Surface shown as background …
avoid areas in warmer tones
(red) and favor locating in
cooler tones (green)
Standardized
Alternative
Routes
Built
Natural
Engineering
Simple
Built-up Area (avoid)
Less Suitable
Open Field
(favor)
More Suitable
…based on the
detailed field data,
the Siting Team
investigates the
impacts of the
Alternative Routes
Note: if the additional detailed data warrants, the Siting Team can re-locate portions of the GIS-derived Alternative
Routes but a formal statement of the reasons are required; alignment of a potential route outside of the decision space
requires an exception petition (analogous to land use re-zoning)
Evaluating Potential Routes (selecting the Preferred)
…the relative merits of
top few potential routes
are discussed by the
Siting Team and then
ranked to identify the
most preferred route
GIS-derived Scores
Expert Judgment
Prescription
 Increasing Abstraction —
Description
The Softer Side of GIS (Beyond Mapping III Epilog)
Map Types
Spatial
Processing
Facts
Base
– measured features,
conditions and
characteristics
Collect
– Earth circumference is 24,900 mi
– Britney Spears was born 12/2/1981
– Britney Spears is 25 years old
Philosopher's Levels of
Cognitive Levels of
Understanding
Judgment
Data
– all facts
– the temperature is 32o F
:
(fact)
– direct acquisition of
primary information
(e.g. elevation)
Where we have been
in GIS
Calculate
Derived
Information
Relevant Facts
– facts within
a context
– the temperature
is 32o F
Knowledge
– interrelationships
among relevant facts
– inferred conditions
and characteristics
(implied fact)
– uses algorithms to
derive secondary
information
(e.g., slope)
Perception
Interpreted
– it sure is cold
– it’s not cold
– adjusted to reflect
expertise and
presumption
(Alaskan)
(judgment)
– I hate this weather
– I love this weather
– potential solution
within model logic and
expression
– “what if”
investigation of
alternative scenarios
(Alaskan)
(conjoined judgment)
(multiple perspectives)
(Floridian)
Calibrate/Weight
– translates information
into relative scales
(preference & importance)
Where
we are headed
in GIS
Modeled
Simulate
Opinions/Values
Wisdom
– actionable
knowledge
(Floridian)
Where Have We Been?
Computer Mapping -- Spatial dB Management -- GIS

Modeling
Spatial Analysis — “contextual” relationships within and among mapped
data (Reclassify, Overlay, Distance, and Neighbors)

Surface Modeling — maps the “spatial distribution” and
pattern of point data (Map Generalization, Spatial Interpolation
and Others)

Data Mining — “numerical” relationships
within and among mapped data (Descriptive, Predictive,
and Prescriptive)
From mapping to
Spatial Reasoning
…changing our Map Paradigm
Thinking with Maps!
(Berry)
More on Map Analysis and GIS Modeling
www.innovativegis.com/basis
Online
Papers
Online
Materials
Hardcopy
Books
Software
(Berry)