subsetmap function

Storing a Part of a Map

subsetmap is used to store a part of any given map of class SpatialPixelsDataFrame into an other object.

subsetmap(x, xlim = NULL, ylim = NULL, ...)

Arguments

• x: an object of class SpatialPixelsDataFrame
• xlim: numerical vector of length 2. The x limits of the rectangle including the new map
• ylim: numerical vector of length 2. The y limits of the rectangle including the new map
• ...: further arguments passed to or from other methods

Details

If xlim or ylim are not provided, the function asks the user to click on the map to delimit the lower left corner and the higher right corner of the new map (see Examples).

Returns

Returns an object of class SpatialPixelsDataFrame

Author(s)

Clement Calenge clement.calenge@ofb.gouv.fr , improvements by Jon Olav Vik

Examples

data(lynxjura)
map <- lynxjura$map

## limits of the new map:
xl <- c(839938.7, 858990.8)
yl <- c(2149019, 2168761)

## computation of the new map:
su <- subsetmap(map, xlim = xl, ylim = yl)
su

## Display
opar <- par(mar = c(0,0,0,0))
layout(matrix(c(1,1,1,1,1,1,1,1,2), byrow = TRUE, ncol = 3))
image(map, axes = FALSE)
polygon(c(xl[1], xl[2], xl[2], xl[1]),
        c(yl[1], yl[1], yl[2], yl[2]))
image(su, axes = FALSE)
box()

par(opar)
par(mfrow = c(1,1))

## Not run:

 ## Interactive example 
 su <- subsetmap(map)

 image(su)
## End(Not run)