chooseRegion function

Interaction with trellis objects.

chooseRegion provides a set of points (in the form of a SpatialPoints) inside a region defined by several mouse clicks. identifyRaster labels and returns points of a trellis

graphic according to mouse clicks. methods

chooseRegion(sp = TRUE, proj = as.character(NA))
## S4 method for signature 'Raster'
identifyRaster(object, layer=1, values=FALSE, pch=13, cex=0.6, col='black',...)

Arguments

• sp: logical, if TRUE the result is a SpatialPoints

  object, otherwise it is a logical vector as returned by in.out

• proj: A character string for the proj4string of SpatialPoints.

• object: A Raster object.

• layer: A numeric or character which should indicate the layer to be chosen.

• values: logical, if TRUE the values are returned.

• pch, cex, col: Graphical parameters for panel.identify

  and panel.link.splom.

• ...: Additional arguments for trellis.focus,panel.link.splom and panel.identify.

Details

When called, these functions wait for the user to identify points (in the panel being drawn) via mouse clicks. Clicks other than left-clicks close the region (for chooseRegion) and the procedure (for identifyRaster).

Note

chooseRegion needs the package mgcv to be installed.

Author(s)

Oscar Perpiñán Lamigueiro

See Also

panel.identify,panel.link.splom, trellis.focus, grid.locator

Examples

library(raster)

f <- system.file("external/test.grd", package="raster")
r <- raster(f)
levelplot(r)
##Do not close the last graphical window
##Use the left button of the mouse to identify points and the right button to finish
chosen_r <- identifyRaster(r, values=TRUE)
chosen_r
s <- stack(r, r-500, r+500)
levelplot(s)
chosen_s <- identifyRaster(s, values=TRUE)
chosen_s

## Not run:

##The package mgcv is needed for the next example
##Use the left button of the mouse to build a border with points, and the right button to finish.
##The points enclosed by the border will be highlighted and returned as a SpatialPoints object.
levelplot(s)
reg <- chooseRegion()
summary(reg)
## End(Not run)

## Not run:

##Solar irradiation data from CMSAF http://dx.doi.org/10.5676/EUM_SAF_CM/RAD_MVIRI/V001

dataURL <- "https://raw.github.com/oscarperpinan/bookvis/master/data/"

old <- setwd(tempdir())
download.file(paste0(dataURL, "SISmm2008_CMSAF.zip"),
   "SISmm2008_CMSAF.zip", method='wget')
unzip("SISmm2008_CMSAF.zip")

listFich <- dir(pattern='\\.nc')
stackSIS <- stack(listFich)
stackSIS <- stackSIS*24 ##from irradiance (W/m2) to irradiation Wh/m2
setwd(old)

idx <- seq(as.Date('2008-01-15'), as.Date('2008-12-15'), 'month')

SISmm <- setZ(stackSIS, idx)
names(SISmm) <- month.abb

levelplot(SISmm)

##Do not close the last graphical window
##Interaction
##Use the left button of the mouse to identify points and the right button to finish
chosen <- identifyRaster(SISmm, layer=3, values=TRUE)
chosen
##Use the left button of the mouse to build a border with points, and the right button to finish.
##The points enclosed by the border will be highlighted and returned as a SpatialPoints object.
reg <- chooseRegion()
summary(reg)
## End(Not run)