R: Geometric subsetting

select {raster} | R Documentation

## Geometric subsetting

### Description

Geometrically subset Raster* or Spatial* objects by drawing on a plot (map).

### Usage

    ## S4 method for signature 'Raster'
    select(x, use='rec', ...)

    ## S4 method for signature 'Spatial'
    select(x, use='rec', draw=TRUE, col='cyan', size=2, ...)

### Arguments

`x` | Raster*, SpatialPoints*, SpatialLines*, or SpatialPolygons*
`use` | character: 'rec' or 'pol'. To use a rectangle or a polygon for selecting
`draw` | logical. Add the selected features to the plot?
`col` | color to use to draw the selected features (when `draw=TRUE)`
`size` | integer > 0. Size to draw the selected features with (when `draw=TRUE)`)
`...` | additional arguments. None implemented

### Value

Raster* or Spatial* object

### See Also

`click, crop`

### Examples

    ## Not run:

    # select a subset of a RasterLayer
    r <- raster(nrow=10, ncol=10)
    values(r) <- 1:ncell(r)
    plot(r)
    s <- select(r) # now click on the map twice

    # plot the selection on a new canvas:
    x11()
    plot(s)

    # select a subset of a SpatialPolygons object
    p1 <- rbind(c(-180,-20), c(-140,55), c(10, 0), c(-140,-60), c(-180,-20))
    hole <- rbind(c(-150,-20), c(-100,-10), c(-110,20), c(-150,-20))
    p2 <- rbind(c(-10,0), c(140,60), c(160,0), c(140,-55), c(-10,0))
    p3 <- rbind(c(-125,0), c(0,60), c(40,5), c(15,-45), c(-125,0))
    pols <- SpatialPolygons( list(  Polygons(list(Polygon(p1), Polygon(hole)), 1),
          Polygons(list(Polygon(p2)), 2), Polygons(list(Polygon(p3)), 3)))
    pols@polygons[[1]]@Polygons[[2]]@hole <- TRUE

    plot(pols, col=rainbow(3))
    ps <- select(pols) # now click on the map twice
    ps

    ## End(Not run)

[Package raster version 3.3-7 Index]