roundSum {lulcc}

Round elements in matrix or data.frame rows

Description

Round all numbers in a matrix or data.frame while ensuring that all rows sum to the same value.

Usage

roundSum(x, ncell, ...)

Arguments

x

matrix or data.frame

ncell

numeric specifying the target sum for each row in x

...

additional arguments (none)

Details

The main application of roundSum is to ensure that each row in the demand matrix specifies exactly the number of cells to be allocated to each land use category for the respective timestep. It may also be used to convert the units of demand to number of cells.

Value

A matrix.

Examples

## Sibuyan Island

## load observed land use data and create demand scenario
obs <- ObsLulcRasterStack(x=sibuyan$maps,
                    pattern="lu",
                    categories=c(1,2,3,4,5),
                    labels=c("Forest","Coconut","Grass","Rice","Other"),
                    t=c(0,14))

dmd <- approxExtrapDemand(obs, tout=0:14)
apply(dmd, 1, sum)

## artificially perturb for illustration purposes
dmd <- dmd * runif(1)
apply(dmd, 1, sum)

## use roundSum to correct demand scenario
ncell <- length(which(!is.na(getValues(sibuyan$maps$lu_sib_1997))))
ncell
dmd <- roundSum(dmd, ncell=ncell)
apply(dmd, 1, sum)