Extract by index

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Indexing to extract values of a Raster* object

These are shorthand methods that call other methods that should normally be used, such as getValues, extract, crop.

object[i] can be used to access values of a Raster* object, using cell numbers. You can also use row and column numbers as index, using object[i,j] or object[i,] or object[,j]. In addition you can supply an Extent, SpatialPolygons, SpatialLines or SpatialPoints object.

If drop=TRUE (the default) cell values are returned (a vector for a RasterLayer, a matrix for a RasterStack or RasterBrick). If drop=FALSE a Raster* object is returned that has the extent covering the requested cells, and with all other non-requested cells within this extent set to NA.

If you supply a RasterLayer, its values will be used as logical (TRUE/FALSE) indices if both Raster objects have the same extent and resolution; otherwise the cell values within the extent of the RasterLayer are returned.

Double brackes '[[ ]]' can be used to extract one or more layers from a multi-layer object.

Keywords
methods, spatial
Methods

x[i]

x[i,j]

Arguments rll x a Raster* object i cell number(s), row number(s), a (logical) RasterLayer, Spatial* object j column number(s) (only available if i is (are) a row number(s)) drop If TRUE, cell values are returned. Otherwise, a Raster* object is returned

See Also

getValues, setValues, extract, crop, rasterize

Aliases
  • [[,Raster,ANY,ANY-method
  • [,Raster,Spatial,missing-method
  • [,Raster,RasterLayer,missing-method
  • [,Raster,Extent,missing-method
  • [,Raster,numeric,numeric-method
  • [,Raster,numeric,missing-method
  • [,Raster,missing,numeric-method
  • [,Raster,matrix,missing-method
  • [,Raster,missing,missing-method
  • [,Raster,logical,missing-method
  • [,Extent,numeric,missing-method
  • [,Extent,missing,missing-method
Examples
# NOT RUN {
r <- raster(ncol=10, nrow=5)
r[] <- 1:ncell(r) 

r[1]
r[1:10]
r[1,]
r[,1]
r[1:2, 1:2]

s <- stack(r, sqrt(r))
s[1:3]
s[[2]]

# }
Documentation reproduced from package raster, version 2.9-5, License: GPL (>= 3)

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