reproducible (version 0.2.0)

fastMask: Faster operations on rasters

Description

This alternative to raster::mask is included here.

Usage

fastMask(x, y)

Arguments

x

A Raster* object.

y

A SpatialPolygons object. If it is not in the same projection as x, it will be reprojected on the fly to that of x

Value

A Raster* object, masked (i.e., smaller extent and/or several pixels converted to NA)

Examples

# NOT RUN {
library(raster)

Sr1 <- Polygon(cbind(c(2, 4, 4, 0.9, 2), c(2, 3, 5, 4, 2)))
Sr2 <- Polygon(cbind(c(5, 4, 2, 5), c(2, 3, 2, 2)))
Sr3 <- Polygon(cbind(c(4, 4, 5, 10, 4), c(5, 3, 2, 5, 5)))

Srs1 <- Polygons(list(Sr1), "s1")
Srs2 <- Polygons(list(Sr2), "s2")
Srs3 <- Polygons(list(Sr3), "s3")
shp <- SpatialPolygons(list(Srs1, Srs2, Srs3), 1:3)
d <- data.frame(vals = 1:3, other = letters[3:1], stringsAsFactors = FALSE)
row.names(d) <- names(shp)
shp <- SpatialPolygonsDataFrame(shp, data = d)
poly <- list()
poly[[1]] <- raster(raster::extent(shp), vals = 0, res = c(1, 1))
poly[[2]] <- raster(raster::extent(shp), vals = 1, res = c(1, 1))
origStack <- stack(poly)
# original mask function in raster
newStack1 <- mask(origStack, mask = shp)
newStack2 <- fastMask(x = origStack, y = shp)

# test all equal
all.equal(newStack1, newStack2)

newStack1 <- stack(newStack1)
newStack2 <- stack(newStack2)

if (interactive()) {
  plot(newStack2[[1]])
  plot(shp, add = TRUE)
}

# }