Indexing to extract values of a Raster* object
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.
x[i]
x[i,j]
Arguments
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 |
|
r <- raster(ncol=10, nrow=5) values(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]]
Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.