ab.gmu {AIGIS} | R Documentation |
For each 1/8 degree gridcell in California, estimate the expected value contained inside a fire perimeter of specified area. Operates by finding the total value inside the gridcell and multiplying by the appropriate fraction, determined by a call to area2frac
.
ab.gmu(gridgpcobj = gridgpc, gws = gridinws, afracs = gfracs, recvar = 1, recvals = bgvals, appdam = FALSE, trimmedin = TRUE, dr = damrats, maskobj = MASK)
gridgpcobj |
A list object containing gridcells in gpc form as well as indexing vectors. See help for the data object gridgpc for exact form. |
gws |
Grid weights. A list of matrices giving zone indices and overlaps for each gridcell. For now gridinws is the appropriate companion object to gridgpc . |
afracs |
A precalculated vector giving the fraction of land area in each gridcell occupied by a fire of a given area. |
recvar |
An integer indicating which column of the record value matrix to use. That is, what variable is to be interpolated. |
recvals |
A matrix containing the data to be interpolated, with rows corresponding to zones, and columns corresponding to different variables. |
appdam |
CA Wildfire specific. A logical indicating whether or not to apply the empirically derived damage ratio. |
trimmedin |
Whether the overlap weights are provided in matrix form. Must be true for this version. |
dr |
CA Wildfire specific. A vector giving precalculated damage ratios by block group. |
maskobj |
A matrix of ones and zeros noting which gridcells should be used and which omitted |
Returns a matrix of with nrow=nrow(MASK)
and ncol=ncol(MASK)
, where entry value[i,j] corresponds to the expected value for a fire of given size in the gridcell corresponding to MASK[i,j]
.
Benjamin P. Bryant, bryant@prgs.edu
data(bgvals) data(damrats) data(gridgpc) data(gridinws) data(MASK) #Find expected values on houses enclosed by a 200 ha fire. #First, create the (reusable) vector of area fractions: gfracs <- sapply(gridgpc[[1]],area2frac, area=200,units="ha", cap=TRUE) theresult <- ab.gmu(gridgpcobj = gridgpc, gws = gridinws, afrac = gfracs, appdam=FALSE, recvar = 1)