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Compute Canopy Height Model (CHM)

get_chm.Rd

Computes a Canopy Height Model (CHM = DSM - DEM) either by:

  • downloading the necessary DEM and DSM from IGN WMS services using x, or

  • using DEM and DSM rasters directly supplied by the user.

Usage

get_chm(x = NULL, dem = NULL, dsm = NULL, minmax = c(0, 50), ...)

Arguments

x

sf or sfc; Geometry located in France.

dem

SpatRaster representing ground elevation (DEM). Must be supplied only when x is NULL.

dsm

A SpatRaster representing surface elevation (DSM). Must be supplied only when x is NULL.

minmax

numeric length-2 vector giving the accepted CHM range as c(min, max). Default: c(0, 50).

...

Additional parameters passed to get_dem() and get_dem() when x is supplied.

Value

A SpatRaster containing the CHM.

Details

When x is provided, both DEM and DSM are automatically fetched via get_dem() and get_dsm(). When x is not provided, both dem and dsm must be manually supplied.

Output values outside minmax are clamped: negative values are set to NA and excessively high values are capped.

Examples

if (FALSE) { # \dontrun{
# Automatic download mode
chm <- get_chm(x = my_polygon)

# Manual mode
dem <- get_dem(my_polygon)
dsm <- get_dsm(my_polygon)
chm <- get_chm(dem = dem, dsm = dsm)
} # }