stars (version 0.6-0)

stars_subset: subset stars objects

Description

subset stars objects

Usage

# S3 method for stars
[(x, i = TRUE, ..., drop = FALSE, crop = !is_curvilinear(x))
# S3 method for stars
[(x, i, downsample = 0) <- value
st_flip(x, which = 1)

Value

st_flip flips (reverts) the array values along the chosen dimension without(s) changing the dimension properties

Arguments

x

object of class stars

i

first selector: integer, logical or character vector indicating attributes to select, or object of class sf or sfc used as spatial selector; see details

...

further (logical or integer vector) selectors, matched by order, to select on individual dimensions

drop

logical; if TRUE, degenerate dimensions (with only one value) are dropped

crop

logical; if TRUE and parameter i is a spatial geometry (sf or sfc) object, the extent (bounding box) of the result is cropped to match the extent of i using st_crop. Cropping curvilinear grids is not supported.

downsample

downsampling rate used in case i is a stars_proxy object

value

array of dimensions equal to those in x, or a vector or value that will be recycled to such an array

which

character or integer; dimension(s) to be flipped

Details

if i is an object of class sf, sfc or bbox, the spatial subset covering this geometry is selected, possibly followed by cropping the extent. Array values for which the cell centre is not inside the geometry are assigned NA.

in an assignment (or replacement form, [<-), argument i needs to be a stars object with dimensions identical to x, and value will be recycled to the dimensions of the arrays in x.

Examples

tif = system.file("tif/L7_ETMs.tif", package = "stars")
x = read_stars(tif)
x[,,,1:3] # select bands
x[,1:100,100:200,] # select x and y by range
x["L7_ETMs.tif"] # select attribute
xy = structure(list(x = c(293253.999046018, 296400.196497684), y = c(9113801.64775462,
9111328.49619133)), .Names = c("x", "y"))
pts = st_as_sf(data.frame(do.call(cbind, xy)), coords = c("x", "y"), crs = st_crs(x))
image(x, axes = TRUE)
plot(st_as_sfc(st_bbox(pts)), col = NA, add = TRUE)
bb = st_bbox(pts)
(xx = x[bb])
image(xx)
plot(st_as_sfc(bb), add = TRUE, col = NA)
image(x)
pt = st_point(c(x = 290462.103109179, y = 9114202.32594085))
buf = st_buffer(st_sfc(pt, crs = st_crs(x)), 1500)
plot(buf, add = TRUE)

buf = st_sfc(st_polygon(list(st_buffer(pt, 1500)[[1]], st_buffer(pt, 1000)[[1]])),
   crs = st_crs(x))
image(x[buf])
plot(buf, add = TRUE, col = NA)
image(x[buf, crop=FALSE])
plot(buf, add = TRUE, col = NA)
lc = read_stars(system.file("tif/lc.tif", package = "stars"))
x = c(orig = lc, 
      flip_x = st_flip(lc, "x"), 
      flip_y = st_flip(lc, "y"), 
      flip_xy = st_flip(lc, c("x", "y")), 
      along = 3)
plot(x)