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Extract isobaths from a raster

Source: R/isobath-corridors.R
extract_isobaths.Rd

Converts raster contour levels to line features.

Usage

extract_isobaths(
  x,
  depths,
  positive_depth = NULL,
  as = c("SpatVector", "sf"),
  ...
)

Arguments

x

A raster-like object accepted by as_bathy().

depths

Numeric contour levels.

positive_depth

Optional logical. If TRUE, depths are converted to positive values. If FALSE, they are converted to negative values. If NULL, depths are used exactly as supplied.

as

Output type: "SpatVector" or "sf".

...

Additional arguments reserved for future extensions.

Value

Isobath line features as terra::SpatVector by default.

Details

Depth convention is explicit. For rasters stored as negative elevation, either pass negative depths or set positive_depth = FALSE when passing positive depth labels.

See also

make_isobath_corridors()

Examples

bathy <- read_bathy(blueterra_example("bathy"))
extract_isobaths(bathy, depths = c(-40, -60))
#> class       : SpatVector
#> geometry    : lines
#> dimensions  : 2, 3  (geometries, attributes)
#> extent      : 134970.3, 138727.2, 204570.3, 205785.1  (xmin, xmax, ymin, ymax)
#> coord. ref. : NAD83 / Puerto Rico & Virgin Is. (EPSG:32161)
#> names       : level contour_value depth_label
#> type        : <num>         <num>       <num>
#> values      :   -40           -40         -40
#>                 -60           -60         -60