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Prepare a bathymetric or elevation raster

Source: R/prepare.R
prepare_bathy.Rd

Applies common preprocessing steps for terrain analysis: optional projection, resampling, cropping, masking, depth filtering, sign conversion, smoothing, and optional file-backed output.

Usage

prepare_bathy(
  x,
  crs = NULL,
  resolution = NULL,
  extent = NULL,
  mask = NULL,
  depth_range = NULL,
  positive_depth = NULL,
  method = "bilinear",
  smooth = FALSE,
  smooth_window = 3,
  filename = "",
  overwrite = FALSE
)

Arguments

x

A raster-like object accepted by as_bathy().

crs

Optional target CRS passed to project_bathy().

resolution

Optional target cell size. A single value is used for both axes; two values are used as x and y resolution.

extent

Optional crop extent: SpatExtent, numeric xmin, xmax, ymin, ymax, raster, or vector object.

mask

Optional polygon/vector mask.

depth_range

Optional numeric length-two range of retained depths or elevations.

positive_depth

Optional logical. If TRUE, convert output to positive depth. If FALSE, convert output to negative depth/elevation. If NULL, preserve sign convention.

method

Resampling and projection method passed to terra.

smooth

Logical. If TRUE, apply smooth_bathy().

smooth_window

Odd integer focal-window size for smoothing.

filename

Optional output raster path.

overwrite

Logical. Allow overwriting filename.

Value

A terra::SpatRaster.

Details

prepare_bathy() never automatically reprojects or flips depth signs. Those operations occur only when crs or positive_depth are supplied. Distance- based geomorphometry should generally be performed in a projected CRS with linear units.

See also

crop_bathy(), mask_bathy(), depth_filter()

Examples

bathy <- read_bathy(blueterra_example("bathy"))
prepared <- prepare_bathy(bathy, depth_range = c(-90, -20), smooth = TRUE)
prepared
#> class       : SpatRaster
#> size        : 70, 190, 1  (nrow, ncol, nlyr)
#> resolution  : 19.98372, 19.98372  (x, y)
#> extent      : 134960.3, 138757.2, 204531.4, 205930.2  (xmin, xmax, ymin, ymax)
#> coord. ref. : NAD83 / Puerto Rico & Virgin Is. (EPSG:32161)
#> source(s)   : memory
#> varname     : laparguera_slope_bathy
#> name        :    bathy_m
#> min value   :  -87.28957
#> max value   : -20.039104