GeomorphometryGradientMetricsToolbox: Geomorphometry & Gradient Metrics Toolbox

In raff-k/Lslide: Functions for object-oriented image analysis in landslide science

Geomorphometry & Gradient Metrics Toolbox

Description

This toolbox contains different function for calculating geomorphometric indices or gradient models. The toolbox is based on the Geomorphometry & Gradient Metrics Toolbox from Jeffrey Evans. Actually, it supports the computation of 'Linear Aspect', 'Mean Slope', 'Site Exposure Index', 'Landform' (concavity/convexity landform index (Bolstads variant)) and 'Roughness Index'.

Usage

GeomorphometryGradientMetricsToolbox(elevation, slope = NULL,
  aspect = NULL, tool = c("Linear Aspect", "Landfrom", "Mean Slope",
  "SEI", "RI"), params = params, zScale = "1.0",
  output.path = tempdir(), use.link2GI = TRUE,
  defaultGrass = c("C:/OSGeo4W64", "grass-7.2.2", "OSGeo4W64"),
  initGRASS.path = "C:/OSGeo4W64/apps/grass/grass-7.2.2", mask = NULL,
  mask.by.thres = NULL, NODATA = -99999,
  load.ElevationIntoGRASS = TRUE, quiet = TRUE)

Arguments

elevation	RasterLayer with elevation data
slope	RasterLayer with slope values. As default the slope will be computet using RQGIS::run_qgis(alg = "grass7:r.slope.aspect"). Default: NULL
aspect	RasterLayer with aspect values. As default the aspect will be computet using RQGIS::run_qgis(alg = "grass7:r.slope.aspect"). Default: NULL
tool	vector containg the name of tools. Actually, the following are supported: "Linear Aspect", "Landfrom", "Mean Slope", "SEI", "RI". Default: c("Linear Aspect", "Landfrom", "Mean Slope", "SEI", "RI")
params	list of lists containing function parameter for functions in tool. There are basically three parameters defining the (1) "size" of moving window, (2) the filename, and (3) a logical value if the raster shall be written (writeRaster). I.e. for "Linear Aspect" - list(size = 3, filename = "LinAspect.tif", writeRaster = TRUE). Default: see notice
zScale	multiplicative factor to convert elevation units to horizontal units. Default: "1.0"
output.path	path to output folder. Default: tempdir()
use.link2GI	= TRUE
defaultGrass	GRASS GIS path to for initialisation using link2GI. Default: c("C:/OSGeo4W64", "grass-7.2.2", "OSGeo4W64"),
initGRASS.path	GRASS GIS path for initialisation using rgrass7. Default: "C:/OSGeo4W64/apps/grass/grass-7.2.2"
mask	RasterLayer that serves as mask. Default: NULL
mask.by.thres	all values equal and higher than (>=) the threshold is masked. Default: NULL otherwhise numeric. TODO: flexible way to mask ranges or values smaller than.
load.ElevationIntoGRASS	write the elevation input into GRASS GIS. Default: TRUE
quiet	no outputs in console. Default: TRUE

Value

List of RasterLayer containing computed geomorphometric indices or gradient models

Note

• GRASS GIS algorithm (grass7:r.slope.aspect) is similar to ArcGIS slope/aspect

• default for params: list(list(size = 3, filename = "LinAspect.tif", writeRaster = TRUE), list(size = 3, filename = "Landform.tif", writeRaster = TRUE), list(size = 3, filename = "MeanSlp.tif", writeRaster = TRUE), list(size = NA, filename = "SEI.tif", writeRaster = TRUE), list(size = 3, filename.RI = "RI.tif", filename.RIw = "RIw.tif", writeRaster = TRUE))

raff-k/Lslide documentation built on March 29, 2022, 6:52 p.m.