approxExtrapDemand: Extrapolate land use area in time

Description

Extrapolate land use area from two or more observed land use maps to provide a valid (although not necessarily realistic) demand scenario.

Usage

approxExtrapDemand(obs, tout, ...)

Arguments

obs

an ObsLulcRasterStack object containing at least two maps

tout

numeric vector specifying the timesteps where interpolation is to take place. Comparable to the xout argument of Hmisc::approxExtrap

…

additional arguments to Hmisc::approxExtrap

Value

A matrix.

Details

Many allocation routines, including the two included with lulcc, require non-spatial estimates of land use demand for every timestep in the study period. Some routines are coupled to complex economic models that predict future or past land use demand based on economic considerations; however, linear extrapolation of trends remains a useful technique.

Examples

Run this code

# NOT RUN {
## Plum Island Ecosystems

## load observed land use maps
obs <- ObsLulcRasterStack(x=pie,
                   pattern="lu",
                   categories=c(1,2,3),
                   labels=c("forest","built","other"),
                   t=c(0,6,14))

## obtain demand scenario by interpolating between observed maps
dmd <- approxExtrapDemand(obs=obs, tout=c(0:14))

## plot
matplot(dmd, type="l", ylab="Demand (no. of cells)", xlab="Time point",
        lty=1, col=c("Green","Red","Blue"))
legend("topleft", legend=obs@labels, col=c("Green","Red","Blue"), lty=1)

## linear extrapolation is also possible
dmd <- approxExtrapDemand(obs=obs, tout=c(0:50))

## plot
matplot(dmd, type="l", ylab="Demand (no. of cells)", xlab="Time point",
        lty=1, col=c("Green","Red","Blue"))
legend("topleft", legend=obs@labels, col=c("Green","Red","Blue"), lty=1)

# }