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Demand
The DEMAND module of FUTURES determines the quantity of land change expected. This is specified by the user in the demand table as the number of cells to be converted at each time step for each sub-region.
###Preparation of the demand table for Status Quo conditions
Data required
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area developed over time
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observed population over time
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population projections for the years to be simulated
Step 1. Quantify the amount of development that has occurred for each region at each of a selection of historical time steps (for example, the amount of development in each county in 1970, 1980, 1990, and 2000). Data are most often obtained via a remotely sensed land cover product.
Step 2. Determine the population of each region for each of those selected time steps. Data are often obtained from state records.
Step 3. Perform ordinary least squares regression where the amount of development is determined as a function of the population present. Note that depending on the study area, alternative relationships may be more appropriate than a linear trend, a logarithmic relationship for example.
Step 4. Determine the amount of land that will need to be developed to accommodate future populations. This is done by solving the regression equation for each year to be simulated.
Step 5. Calculate the number of grid cells that need to be converted at each time step (equivalent to the amount of land determined above).
Modify the table for different demand scenarios – replace the status quo demand table with the table containing the development amount of interest.
Years_To_Simulate: 36
Year region1 region2 region3 region4 region5 region6 region7 region8 region9
1997 3944 15385 17221 4819 3043 18774 6457 11896 2629
1998 3944 15385 17221 4819 3043 18774 6457 11896 2629
1999 3944 15385 17221 4819 3043 18774 6457 11896 2629
...
2032 2020 9776 5025 1674 1187 6009 2866 9173 3255