elev_to_lighting: Calculate derivatives from the Lighting module

In loreabad6/terrain: Utility Functions for Terrain Derivatives Calculations

Calculate derivatives from the Lighting module

Description

Calculate derivatives from the Lighting module

Usage

elev_to_lighting(
  elev_sgrd,
  out_dir,
  prefix = "",
  envir,
  ...,
  negop = FALSE,
  posop = FALSE,
  shade = FALSE,
  svfct = FALSE,
  visky = FALSE
)

Arguments

elev_sgrd	input, elevation raster data in SAGA format, can be created with elev_to_sgrd()
out_dir	output directory
prefix	character prefix for output filenames
envir	environment to get SAGA installation, can be set with init_saga()
...	ignored, check help page for possible outputs
posop, negop	Topographic Openness: Topographic openness expresses the dominance (positive) or enclosure (negative) of a landscape location. Openness has been related to how wide a landscape can be viewed from any position. It has been proven to be a meaningful input for computer aided geomorphological mapping. Openness is an angular measure of the relation between surface relief and horizontal distance. For angles less than 90", it is equivalent to the internal angle of a cone, its apex at a DEM location, constrained by neighboring elevations within a specified radial distance. Openness incorporates the terrain line-of-sight, or viewshed, concept and is calculated from multiple zenith and nadir angles-here along eight azimuths. Openness has two viewer perspectives. Positive values, expressing openness above the surface, are high for convex forms, whereas negative values describe this attribute below the surface and are high for concave forms. Openness values are mapped by gray-scale tones. The emphasis of terrain convexity and concavity in openness maps facilitates the interpretation of landforms on the surface of the Earth and its seafloor, and on the planets, as well as features on any irregular surface-such as those generated by industrial procedures. Boolean, defaults to FALSE
shade	Hillshade: shaded relief from a surface raster by considering the illumination source angle and shadows. Boolean, defaults to FALSE
svfct, visky	Sky View Factor and Visible Sky: Crucial variable widely used to quantify the characteristics of surface structures and estimate surface radiation budget. The SVF expresses the proportion (ratio) of radiation leaving the sky, assumed isotropic, that is able to reach a ground surface tilted at an arbitrary angle. Its value must vary between the minimum of 0, when the sky is not visible at all and to the maximum of 1, when the ground surface is horizontal and the sky entirely visible. Visible Sky is computed within the same algorithm. Boolean, defaults to FALSE

loreabad6/terrain documentation built on July 6, 2023, 6:44 a.m.