raster: Create a RasterLayer Object from Mask or Dsurface

Description

Methods to convert secr object to a RasterLayer object.

Usage

# S4 method for mask
raster(x, covariate, values = 1, crs = NA)
# S4 method for Dsurface
raster(x, covariate, values = 1, crs = NA)

Arguments

mask or Dsurface object

covariate

character name of covariate to provide values for RasterLayer

values

numeric values for RasterLayer

crs

character or object of class CRS. Optional PROJ.4 type description of a Coordinate Reference System (map projection).

Value

RasterLayer

Details

There are two ways to specify the values to be used. If covariate is provided then the values of the corresponding covariate of the mask or Dsurface are used. Otherwise, values is duplicated to the required number of rows.

The resulting RasterLayer may optionally include a PROJ.4 map projection defined via crs. The specification may be very simple (as in the example below) or complex, including an explicit datum and other arguments. Projections are used by raster, sp, rgdal and other packages. See raster for further explanation and links.

The S3 classes `mask' and `Dsurface' are defined in secr as virtual S4 classes. This enables these extensions to the list of S4 methods defined in raster.

Although these methods work `standalone', it is currently necessary to load the raster package to do much with the result (e.g., plot it).

Examples

Run this code


## Not run: ------------------------------------
# 
# shorePossums <- predictDsurface(possum.model.Ds)
# tmp <- raster(shorePossums, covariate = "D.0")
# library(raster)
# plot(tmp, useRaster = FALSE)
# 
# ## alternative with same result
# tmp <- raster(shorePossums, values = covariates(shorePossums)$D.0)
# 
# ## set the projection
# ## here the crs PROJ.4 spec refers simply to the old NZ metric grid
# tmp <- raster(shorePossums, "D.0", crs = "+proj=nzmg")
# ## check the projection
# proj4string(tmp)
#      
## ---------------------------------------------