Raster Percent Volume

Calculates a percent volume on a raster or based on a systematic sample

raster.vol(x, p = 0.95, sample = FALSE, spct = 0.05)

Arguments

x	raster class object
p	percent raster-value volume
sample	base volume on systematic point sample (TRUE/FALSE)
spct	sample percent, if sample (TRUE)

Value

if sample (FALSE) binary raster object with 1 representing designated percent volume else, if sample (TRUE) n sp SpatialPointsDataFrame object with points that represent the percent volume of the sub-sample

Note

Since this model needs to operate on all of the raster values, it is not memory safe

Author

Jeffrey S. Evans <jeffrey_evans@tnc.org>

Examples

# \donttest{
require(raster)
  r <- raster(ncols=100, nrows=100)
    r[] <- runif(ncell(r), 0, 1)
    r <- focal(r, w=focalWeight(r, 6, "Gauss"))
    r[sample(1000, 1:ncell(r))] <- NA
  
  # full raster percent volume 
  p30 <- raster.vol(r, p=0.30)
  p50 <- raster.vol(r, p=0.50)
  p80 <- raster.vol(r, p=0.80)

opar <- par(no.readonly=TRUE)
    par(mfrow=c(2,2))
    plot(r, col=cm.colors(10), main="original raster")
    plot(p30, breaks=c(0,0.1,1), col=c("cyan","red"), legend=FALSE,
      main="30% volume")
    plot(p50, breaks=c(0,0.1,1), col=c("cyan","red"), legend=FALSE,
      main="50% volume")
    plot(p80, breaks=c(0,0.1,1), col=c("cyan","red"), legend=FALSE,
      main="80% volume")
par(opar)  
# }