rast.grad: Creates gradient rasters from a raster object.
Description
This function takes a raster stack or raster object and creates two
matrices for each raster layer, one which contains the x coordinates
of the gradient of the raster layer and one which contains the y
coordinates of the gradient of the raster layer.
Usage
rast.grad(rasterstack)
Arguments
rasterstack
A raster layer or raster stack from package "raster".
Value
xyA matrix of x and y coordinates of each cell in the raster
stack or raster layer. The order is the order of the cells in the
raster object.
grad.xa matrix where each column is the x-coordinates of the
gradient for one raster layer
grad.ya matrix where each column is the y-coordinates of the
gradient for one raster layer
rast.grad.xA raster stack where each raster layer is the
x-coordinates of the gradient for one covariate
rast.grad.yA raster stack where each raster layer is the
x-coordinates of the gradient for one covariate
Details
The gradient is computed using the "terrain" function in raster.
References
Hanks, E. M.; Hooten, M. B. & Alldredge, M. W. Continuous-time
Discrete-space Models for Animal Movement The Annals of Applied
Statistics, 2015, 9, 145-165