Generate spatial proxies — make

The make_proxy() function generates spatial proxies for a given raster object. It generates three types of proxies: coordinates, Euclidean Distance Fields (EDF), and Oblique Geographic Coordinates (OGC). Additionally, the add_proxy() function can be used to add a proxy to an existing raster object.

make_proxy(rast_grid, type, opts = NULL)

add_proxy(rast_grid, type, opts = NULL)

Arguments

rast_grid: A raster object with the desired dimensions
type: The type of proxy to generate. Options are coordinates ("coordinates"), Euclidean Distance Fields ("edf"), and Oblique Geographic Coordinates ("ogc")
opts: A list of options to pass to the proxy generation function. Only used when type = "edf" or type = "ogc". When type = "edf", the "coords" option is and sf object a matrix with two columns (x, y) representing the coordinates to use when generating Euclidean Distance Fields. When type = "ogc", the "n" option is an integer representing the number of angles to use when generating Oblique Geographic Coordinates.

Value

A SpatRaster object with the generated spatial proxies

References

Behrens, T., Schmidt, K., Viscarra Rossel, R. A., Gries, P., Scholten, T., & MacMillan, R. A. (2018). Spatial modelling with Euclidean distance fields and machine learning. European journal of soil science, 69(5), 757-770.

Møller, A. B., Beucher, A. M., Pouladi, N., & Greve, M. H. (2020). Oblique geographic coordinates as covariates for digital soil mapping. Soil, 6(2), 269-289.

Examples

rast_grid = terra::rast(ncols = 300, nrows = 100, xmin = 0, xmax = 300, ymin = 0, ymax = 100)
proxy_coords = make_proxy(rast_grid, "coordinates")
proxy_edf = make_proxy(rast_grid, "edf")
proxy_ogc = make_proxy(rast_grid, "ogc", opts = list(n = 5))
terra::plot(proxy_coords)

terra::plot(proxy_edf)

terra::plot(proxy_ogc)