makeTerrainDerivatives

Make three band terrain stack from input digital terrain model

Usage

makeTerrainDerivatives(dtm, res, filename)

Arguments

dtm

Input SpatRaster object representing bare earth surface elevations.

res

Resolution of the grid relative to coordinate reference system units (e.g., meters).

filename

Name and full path or path relative to working directory for output terrain stack. We recommend saving the data to either TIFF (".tif") or Image (".img") format.

Value

Three-band raster grid written to disk in TIFF format and spatRaster object.

Details

This function creates a three-band raster stack from an input digital terrain model (DTM) of bare earth surface elevations. The first band is a topographic position index (TPI) calculated using a moving window with a 50 m circular radius. The second band is the square root of slope calculated in degrees. The third band is a TPI calculated using an annulus moving window with an inner radius of 2 and outer radius of 5 meters. The TPI values are clamped to a range of -10 to 10 then linearly rescaled from 0 and 1. The square root of slope is clamped to a range of 0 to 10 then linearly rescaled from 0 to 1. Values are provided in floating point.

The stack is described in the following publication and was originally proposed by William Odom of the United States Geological Survey (USGS):

Maxwell, A.E., W.E. Odom, C.M. Shobe, D.H. Doctor, M.S. Bester, and T. Ore, 2023. Exploring the influence of input feature space on CNN-based geomorphic feature extraction from digital terrain data, Earth and Space Science, 10: e2023EA002845. https://doi.org/10.1029/2023EA002845.

Examples

if (FALSE) {
inDTM <- terra::rast("INPUT DTM NAME AND PATH")
terrOut <- makeTerrainDerivatives(dtm=inDTM,
                                 res=2,
                                 filename="OUT TERRAIN STACK NAME AND PATH")
}