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Calculate Euclidean distance via Python

Source: R/python_dist.R
python_dist.Rd

Function to call python script for calculating Euclidean distances on landscape rasters via arcpy.

Usage

python_dist(
  pathin,
  landscape_name,
  pathout,
  SDM,
  filename = "droost_km.tif",
  scale = NULL,
  mask = NULL,
  overwrite = FALSE
)

Arguments

pathin, landscape_name

Character strings defining the filepath (pathin/landscape_name) where input rasters are located, such as those created from running python_focal_prep() or update_roosts()

pathout, SDM

Additional character strings defining the filepath (pathout/SDM/landscape_name) where output raster should be written

filename

name of the output raster, including file extension; default is 'droost_km.tif', the name of the predictor required by the waterbird models

scale

Optional character string for scaling the results; See Details

mask

Optional SpatRaster or character string giving the filepath to a raster that should be used to mask the output, e.g. a study area boundary

overwrite

Logical; passed to terra::writeRaster(); does not apply to the intermediate step of writing droost_raw.tif

Value

Nothing; all files written to pathout/SDM/landscape_name

Details

Calls the dist_stats.py function to calculate the Euclidean distance for all cells in the input raster without a value to the nearest cell with a value (e.g., for calculating distance to a crane roost or a stream).

Raw python results will be written to pathin/landscape_name/droost_raw.tif, and then optionally scaled and/or masked, before writing the final output to pathout/SDM/landscape_name/. Currently supported scale options include: km to divide the results by 1000 and return distances in kilometers or sqrt to take the square root of the results.

Important: This function requires the availability of arcpy and Spatial Analyst extensions. While these statistics can be entirely calculated in R, arcpy is much faster. Note: the initial raw output from dist_stats.py to pathin/landscape_name/droost_raw.tif will not overwrite existing rasters; old versions must be deleted before re-running.

Examples

# See vignette