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surfaceArea.matrix <- function(m,cellx=1,celly=1,byCell=FALSE){
if(byCell){
mout = matrix(NA,nrow=nrow(m),ncol=ncol(m))
}else{
mout = NA
}
m=cbind(m[,1],m,m[,ncol(m)])
m=rbind(m[1,],m,m[nrow(m),])
ret = .C("sarea",
as.double(m),
as.integer(nrow(m)),
as.integer(ncol(m)),
as.double(cellx),
as.double(celly),
sa=as.double(mout),
bycell=as.integer(byCell),
NAOK=TRUE)
if(!byCell){
return(ret$sa)
}else{
return(matrix(ret$sa,ncol=ncol(mout),nrow=nrow(mout)))
}
}
setMethod("surfaceArea", signature("matrix"), surfaceArea.matrix)
surfaceArea.SpatialGridDataFrame <- function(m,cellx=1,celly=1,byCell=FALSE){
cs = gridparameters(m)$cellsize
ret = surfaceArea(as.matrix(m), cs[1], cs[2], byCell = byCell)
if (is.matrix(ret)) {
m[[1]] = as.vector(ret)
m
} else
ret
}
setMethod("surfaceArea", signature("SpatialGridDataFrame"),
surfaceArea.SpatialGridDataFrame)
surfaceArea.SpatialPixelsDataFrame <- function(m, byCell=FALSE)
surfaceArea(as(m, "SpatialGridDataFrame"), byCell = byCell)
setMethod("surfaceArea", signature("SpatialPixelsDataFrame"),
surfaceArea.SpatialPixelsDataFrame)
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