MC2toPath (version 0.0.16)

AggregateVegFracs: Aggregate vegetation fractions

Description

Sometimes it is useful to combine the vegetation fractions for several MC2 vegetation types, corresponding to different PVTs. AggregateVegFracs provides that capability.

Usage

AggregateVegFracs(vegChangesLocal, vt2pvtlutLocal, pvts2aggregate)

Arguments

vegChangesLocal

vegChangesLocal is a list of 5 named items: tgtfile, years, vts2keep, vtFracsReduced, changeFracsReduced tgtfile is the path and file name of the input netCDF file years is a vector of the calendar years represented in the change data, e.g. 2011, 20

vt2pvtlutLocal

vt2pvtlutlocal ("VTYPE to PVT lookup table") is a data frame with 3 columns: VT, PVT, and Stratum. The VT column has the MC2 VTYPE integer value. The PVT column has a corresponding 3-letter potential vegetation type abbreviation such as "fdg", "fvg", et

pvts2aggregate

pvts2aggregate is a vector of 3-letter PVT abbreviations, e.g. "fdw", "fvg"

Value

• Returns a vector of fractions, one for each calendar year in the input data. Each fraction represents the fraction of all the active gridcells which is occupied by any of the vegetation types associated with the PVTs in the pvts2aggregate list.

Examples

## The function is currently defined as
function (vegChangesLocal, vt2pvtlutLocal, pvts2aggregate) 
{
    years = vegChangesLocal[[2]]
    nYrs = length(years)
    vts = vegChangesLocal[[3]]
    nVTs = length(vts)
    ndxsOfVTs2aggregate = c()
    nPVTs = length(pvts2aggregate)
    pvts2aggregateNdx = 1
    while (pvts2aggregateNdx <= nPVTs) {
        tgtPVT = pvts2aggregate[[pvts2aggregateNdx]]
        found = FALSE
        vtNdx = 0
        while (vtNdx < nVTs && !found) {
            vtNdx = vtNdx + 1
            vt = vt2pvtlutLocal$VT[vtNdx]
            pvt = levels(vt2pvtlutLocal$PVT)[vt2pvtlutLocal$PVT[vtNdx]]
            cat(c("tgtPVT, vtNdx, vt, pvt = ", tgtPVT, vtNdx, 
                vt, pvt, ""))
            if (pvt == tgtPVT) {
                ndxsOfVTs2aggregate = c(ndxsOfVTs2aggregate, 
                  vtNdx)
                pvts2aggregateNdx = pvts2aggregateNdx + 1
                found = TRUE
                cat(c("found vt ", vt, "at vtNdx ", vtNdx, "for tgtPVT ", 
                  tgtPVT, ""))
            }
        }
        stopifnot(found)
    }
    stopifnot(length(ndxsOfVTs2aggregate) == nPVTs)
    aggFracs = array(0, nYrs)
    vtFracs = vegChangesLocal[[4]]
    stopifnot(dim(vtFracs)[1] == nVTs)
    stopifnot(dim(vtFracs)[2] == nYrs)
    for (aggNdx in 1:nPVTs) {
        vtNdx = ndxsOfVTs2aggregate[aggNdx]
        vt = vt2pvtlutLocal$VT[vtNdx]
        cat(c("vtNdx, vt = ", vtNdx, vt, ""))
        aggFracs = aggFracs + vtFracs[vtNdx, ]
    }
    return(aggFracs)
  }