The effect of Land Use Cover Change model resolution on scale of aggregation AAG Meeting _ March...
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Transcript of The effect of Land Use Cover Change model resolution on scale of aggregation AAG Meeting _ March...
The effect of Land Use Cover The effect of Land Use Cover Change model resolution on scale of Change model resolution on scale of
aggregationaggregation
AAG Meeting _ March 2006Amélie Davis & Dr. Bryan Pijanowski
March 8, 2006AAG MEETINGChicago, Illinois
OutlineOutline
► Agricultural expansion scenarios for East African countries based on Land Transformation Model (LTM) results and UN Population estimates
► Urbanization scenarios based on Multi- Criteria Evaluation (MCE) and UN Population estimates
► Scaling issues and aggregation errors
March 8, 2006AAG MEETINGChicago, Illinois
LTM for Agricultural ExpansionLTM for Agricultural Expansion
• Land use change forecast model using neural networks
• Forecast Agricultural expansion based on future UN population estimates
• Drivers:
_ _
_ _
_ _
March 8, 2006AAG MEETINGChicago, Illinois
Diagram of StepsDiagram of Steps
Figure out which drivers to include
Figure out the number or urban cells per country
Calculate ratio people per Ag Cells in
landscape
Use ratio to extrapolate pop urban to 2050 by 5
year increments
Run LTM on East Africa to forecast agricultural expansion pick best
PCM
Project Agricultural use using LTM neural
network outputs
Mask out water bodies, parks and agriculture
Include Urban expansion (use different
method)
March 8, 2006AAG MEETINGChicago, Illinois
Agriculture Forecast: Agriculture Forecast: 2005 (left) 2030 (right)2005 (left) 2030 (right)
March 8, 2006AAG MEETINGChicago, Illinois
Results for East AfricaResults for East Africa
• 2005 to 2030 in 5year increments
• Notice that Uganda “runs out” of agricultural space by 2020
March 8, 2006AAG MEETINGChicago, Illinois
Urbanization SimulationUrbanization Simulation
Use Multi-Criterion Evaluation• Based on 1983 book by Voogd & 1991 paper by Carver et al. • Also part of IDRISI software• Similar to LTM in the use of drivers• Uses expert judgment to weigh input
drivers• Simple implementation in GIS
March 8, 2006AAG MEETINGChicago, Illinois
6 drivers for Urbanization6 drivers for Urbanization Distance to urban Focal sum of urban close Focal sum of urban
far
Distance to roads a roads b roads c
March 8, 2006AAG MEETINGChicago, Illinois
• Standardization of drivers from zero to one with larger number being more likely to urbanize.
Ex: dist to road: max - # / min-max• Pair wise comparison of each driver to establish
their weights.
Ex: distance to urban is extremely more important when compared to distance to roads
Based on ‘expert’ judgment
Steps for MCESteps for MCE
March 8, 2006AAG MEETINGChicago, Illinois
• Approximate weight calculation• Implement them in raster calculatorEx: multiply your drivers by their weights. Make sure
you exclude the cells which cannot urbanize (already urban, parks, lakes, ocean)
Problem city boundaries are too smooth.
Resemble edges of focal sum drivers Multiply those 2 drivers by a
random map
Weighing of Drivers Weighing of Drivers
March 8, 2006AAG MEETINGChicago, Illinois
2001
2001
2050
2005
2030
March 8, 2006AAG MEETINGChicago, Illinois
East Africa Urbanization East Africa Urbanization
• MCE map • Red/orange =
greatest likelihood of urbanization
• Problems with Ethiopia and Mozambique
not enough information in drivers
March 8, 2006AAG MEETINGChicago, Illinois
Urban in 2000Urban in 2000
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2005Urban Forecast for 2005
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2010Urban Forecast for 2010
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2015Urban Forecast for 2015
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2020Urban Forecast for 2020
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2025Urban Forecast for 2025
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2030Urban Forecast for 2030
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2035Urban Forecast for 2035
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2040Urban Forecast for 2040
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2045Urban Forecast for 2045
March 8, 2006AAG MEETINGChicago, Illinois
Urban Forecast for 2050Urban Forecast for 2050
March 8, 2006AAG MEETINGChicago, Illinois
Same MCE but for Nairobi at 1km Same MCE but for Nairobi at 1km spatial resolutionspatial resolution
March 8, 2006AAG MEETINGChicago, Illinois
1km MCE Results1km MCE Results
• Original urban in red• Urbanization in green
2005
2050
2025
March 8, 2006AAG MEETINGChicago, Illinois
Modeling ImplicationsModeling Implications
• Visually maximum ‘smooth’ transitioning of urbanization at 1km seems to be 5 years
• Patterns of urbanization with same method but different spatial resolution are different
Which model do you use?
Should weights be reevaluated for different spatial resolutions?
1km resolution 90m resolution resampled at 1km
March 8, 2006AAG MEETINGChicago, Illinois
Scaling IssuesScaling Issues
• Different
Patterns
• Different information passed on to climate model
March 8, 2006AAG MEETINGChicago, Illinois
Conclusions and Next StepsConclusions and Next Steps
• Merge Urbanization with Agricultural expansion maps
• Study the interaction of different fractional covers of urban at varying spatial resolutions of the LULCC change map with disparate spatial resolution climate grid which scale will be best suited to couple both models?
• How will shape and patterns within the landscape influence this coupling?
March 8, 2006AAG MEETINGChicago, Illinois
March 8, 2006AAG MEETINGChicago, Illinois