Make three band terrain stack from input digital terrain model using terra
Usage
makeTerrainVisTerra(
dtm,
cellSize = 1,
innerRadius = 2,
outerRadius = 10,
hsRadius = 50,
writeRaster = FALSE,
outName
)Arguments
- dtm
Input SpatRaster object representing bare earth surface elevations.
- cellSize
Resolution of the grid relative to coordinate reference system units (e.g., meters).
- innerRadius
inner radius of annulus moving window used for local TPI calculation. Default is 2.
- outerRadius
outer radius of annulus moving window used for local TPI calculation.
- hsRadius
outer radisu for circular moving window used for hillslope TPI calculation.
- writeRaster
TRUE or FALSE. Save output to disk. Default is TRUE.
- outName
Name of output raster with full file path and extension.
Details
This function creates a three-band raster stack from an input digital terrain model (DTM) of bare earth surface elevations using terra. This implementation is slower than the torch-based implementation, especially when the torh-based implementation uses GPU-based computation.
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 ange 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.