landscape modeling for blue wing teal in the sheboygan river basin: a weighted criterion approach c....
TRANSCRIPT
Landscape Modeling for Blue Wing Teal in the Sheboygan
River Basin: A Weighted Criterion
Approach
C. Pekar, October 1, 2009Advisor: Dr. Todd Bacastow
Overview
• The Problem of Weighting Criteria
•Discussion of Analytic Hierarchy Process
•Discussion of Sheboygan River Basin, Wetland Restoration and Blue Wing Teal
•Review of Related Projects
•Proposed Project Sequence
Traditional GIS- based site selection processes often fail to assign weights to input criteria layers.
Problem
1 0 1
2 1 0
2 0 0
1 0 0
1 2 1
1 2 1
2 0 1
3 3 1
3 2 1
Layer 1
Layer 2
OutputLayer
+
=
Vs.
1 0 1
2 1 0
2 0 0
1 0 0
1 2 1
1 2 1
1 0 .25
1.25 1.75 .75
1.25 1.5 .75
Layer 1(.25)
Layer 2(.75)
OutputLayer
+
=
The Analytic Hierarchy Process creates a framework which ascribes numerical weightings to subjective preferences.
Solution
What does it do?It allows users to break down complex problems into a hierarchy of a goal and subordinate features .
How does it relate to GIS?AHP can be used to determine the weights of different data layers
(criteria) used in a raster-based site-selection analysis.
How are the weights determined?One of the cornerstones of the AHP is the “pairwise comparison” of every
combination of criteria using the “Fundamental Scale of Absolute Numbers”.
This is performed by an expert panel. The results are imported into a matrix and from which the weights are derived.
Traditional depiction of AHP.
Goal
Criteria 2 Criteria 1 Criteria 4 Criteria 3
Alt. 1 Alt. 2 Alt. 3
Fundamental Scale of Absolute Numbers
Intensity of Importance
Definition Explanation
1 Equal Importance Two criteria contribute equally to the objective
3 Moderate Importance Experience and judgment slightly favor one criteria over another
5 Strong Importance Exp. and judgment strongly favor one criteria over another
7 Very Strong Importance
One criteria is strongly favored over another
9 Extreme Importance The evidence favoring one criteria over another is of the highest possible order of affirmation
2, 4, 6, 8 Intermediate Values
Reciprocals of Above
Values for Inverse Comparison
Adapted from Saaty, 2005 and Marinoni, 2004
Example Pairwise Comparison Matrix – Identifying Suitable Sites for Gravel Pits
Adapted from Marinoni, 2006
WPZ Dist Over-burden
Thick-ness
Soil Prod.
WPZ 1 1/4 5 5 1/2
Dist 4 1 7 7 4
Over-burden
1/5 1/7 1 1/4 1/5
Thick-ness
1/5 1/7 4 1 1/7
Soil Prod.
2 1/4 5 7 1
WPZ = Water Protection ZoneDist = Distance to Settlements (m)Overburden = Thickness of Overburden (m)Thickness = Thickness of Desired MaterialSoil Prod. = Agricultural Productivity of Soils
Establishing Criteria Weights – (Doing the Math!)
From Nekhay, Arriaza and Guzman-Alvarez, 2008
n = criteriaw = comparison scores (1-9)
On Consistency
Criteria 2 Criteria 1
Criteria 3
The Consistency Ratio provides a measure to ensure consistency exists amongst the criterion weightings.
Example of Resulting Suitability Map – Evaluation of Iberian Lynx Habitat Restoration Potential for Olive Groves in Southern Spain
From Nekhay and Arriaza, 2009
How does this fit into organizational decision making?
“…the Spatial Decision Support System itself is not a decision maker. Its purpose is to give recommendations to the
decision makers.” (Marinoni and Hoppe, 2006)
Other Concerns – Group Dynamics• Scheduling Conflicts• Groupthink• Dominant Voice• “Comparison Fatigue”
Why Potentially Restorable Wetlands in the Sheboygan
River Basin?
Historic Statewide Wetland LossOver 50% of the wetlands in the state have been lost since European settlement.
EPA Area of Concern•Legal designation by USEPA for the most polluted waterways in Great Lakes Region•32 of the 35 are in the U.S.•Our best opportunity for restoring the health of the Great Lakes is to recover the ecological services of these river basins and get them de-listed (clean).
Why the Intent on Improving Blue Wing Teal Breeding
Habitat?
From Wisconsin DNR
Population DeclineWhile other waterfowl populations in Wisconsin have stabilized or are increasing, the Blue Wing Teal population is still trending downwards.
From Wisconsin DNR
Also, the Blue Wing Teal is considered a Focal Species by the Upper Mississippi River and Great Lakes Region Joint Venture.
Conservation StatusThe Blue Wing Teal is listed as a Wisconsin Species of Greatest Conservation Need by the Wisconsin Department of Natural Resources.
Related Projects
Milwaukee River Basin Wetland Assessment Project•Vector-based analysis created Potentially Restorable Wetland layer for the Milwaukee River Basin.•Input layers limited to NRCS soil units, WI Wetland Inventory, and WiscLAND Landcover.
Sheboygan River Basin Conservation Mapping Tool•Raster-based analysis using watersheds and sub-watersheds as the unit level of analysis within the Sheboygan River Basin.•Ranked watersheds and sub-watersheds according to criteria such as Migratory Bird Habitat Model, Natural Landcover, Percent of Sub-watershed that is Wetland, and Percent of Sub-watershed with Potentially Restorable Wetlands.•“With some GIS expertise, there are numerous data combinations and score ‘weighting’ that could be done with the mapping tool to customize the prioritization of sub-watersheds”.
1. Communicate goal to stakeholders.2. Identify 15-20 potential criteria layers.3. Determine up to 10 criteria layers with subgroup of expert panel.4. Determine values for intra-layer alternatives with subgroup of expert
panel.5. Present criteria and values to expert panel for acceptance.6. Make any revisions to criteria or scoring of intra-layer alternatives.7. Reclassify data layers to reflect determined values and import layers
into the GIS.8. Email survey with “pairwise comparisons” to expert panel.9. Average results from survey and execute preliminary analysis to
calculate criteria layer weightings and determine Consistency Ratio.10. Present weightings and Consistency Ratio to expert panel for
acceptance.11. Make any revisions as necessary.12. Finalize analysis and create suitability mapping.13. Identify highest ranking sites for further analysis and field
evaluation.14. Compare Primary Output Map with 1) unweighted version of output
map and 2) baseline PRW layer
Proposed Process
Functional Wetland Restoration Layers•Soils•Slope•WI Wetland Inventory•Landcover•Proximity to Waterbodies•Ditches •Reed Canary Grass
Teal Specific Layers•Migratory Bird Stopover Model (by subwatershed)•Historic Wetland Loss (by subwatershed)•Percent Grassland (by subwatershed)•Percent Wetland (by subwatershed)•Percent Forest (by subwatershed)•Distance from Forested Tracts•Known Breeding Occurrences of Blue Wing Teal
Potential Search Criteria
• October • Finalize Criteria• Prepare Survey• Acquire Remaining Data Layers• Submit Conference Abstract
• November• Present Criteria to Expert Panel• Distribute Survey• Reclassify Raster Data• Collect Survey Data and Determine Weights/Verify Consistency
Index• Present Weightings and Consistency Ratio to Panel for Acceptance
• December• Begin Analysis
• January• Complete Analysis• Complete Draft Report
• February• Finalize Report and Present Findings to Expert Panel
• March• Present Paper at American Water Resources Association Conference
Project Timeline
How Could this Possibly Go Wrong?
Concern Safety Valve
Lack of Consensus on Criteria?
Short-list of Experts Determining Criteria
Scheduling Conflict? Surveys to be Delivered Electronically
Experts Uncomfortable with Resulting Weightings?
Opportunity to Modify Pairwise Rankings
Questions?
From Wisconsin DNR