I've 10 drivers in model, 4 of which are dynamic variables (i.e., distance to economic centers, population densities, distance to roads, and distance to built-up areas). I've successfully implemented the distance to roads and built-up as dynamic variables into the model. However, the other two were not as successful and the main issue is related on how to control "when to replace the variable". To give an example, I will stick with the population density driver.
EXAMPLE ISSUE: I've been trying to use the population variable as a dynamic input with the intention to replace the original population driver layer with new future ones when their time is reached. Referring to the manual, this should be performed by writing a macro script for the population driver. However, I tried writing a Macro script but could not find a function that performs a logical test on prediction STAGE TIME prior to implementing the new population layer. Instead, from the first stage, the prediction model uses the new population layer (although the time of that layer is still in the future). To transfer my text with numerical values:
- Assume my current LULC map is for 2020
- Assume my population density layer is for 2020
- Assume that I have population predictions for 2030 and 2040.
- Assuming that I want to predict LULC for 2050 while using population as a dynamic variable.
-> this would imply that the written Macro should replace the population density layer 2 times, one when the prediction stage is after year 2030, a second when the prediction stage is after 2040. However, I have not found a function in the Macro that checks the time condition prior to recalculating the population density driver.
Is this a solution to this problem? How to include the population density as a dynamic variable within LCM interface? It seems to me that the Macro option has an infinite possibilities to calculate the dynamic variable but it is still restricted to variables related to LAND COVER or ROADS? Is this a correct assessment of the macro environment within LCM?