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Build isobath corridors

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

Buffers isobath contour lines to create depth-following corridor polygons.

Usage

make_isobath_corridors(
  x,
  depths,
  width,
  smooth = FALSE,
  as = c("SpatVector", "sf"),
  positive_depth = NULL,
  ...
)

Arguments

x

A raster-like object accepted by as_bathy().

depths

Numeric contour levels.

width

One-sided buffer distance in map units. The nominal full corridor width is twice this value.

smooth

Logical. If TRUE, apply a zero-width buffer after buffering to clean polygon topology.

as

Output type: "SpatVector" or "sf".

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.

...

Additional arguments reserved for future extensions.

Value

Isobath corridor polygons as terra::SpatVector by default.

Details

width is interpreted as a one-sided buffer distance in the CRS map units. Projected CRS are strongly recommended. If the raster uses longitude/latitude, the function warns before buffering because distance interpretation may be misleading. Corridors are returned as independent buffers and can overlap; their summaries are therefore not mutually exclusive or additive.

See also

extract_isobaths(), summarize_isobath_terrain()

Examples

bathy <- read_bathy(blueterra_example("bathy"))
make_isobath_corridors(bathy, depths = c(-40, -60), width = 5)
#> class       : SpatVector
#> geometry    : polygons
#> dimensions  : 2, 7  (geometries, attributes)
#> extent      : 134965.3, 138732.2, 204565.3, 205790.1  (xmin, xmax, ymin, ymax)
#> coord. ref. : NAD83 / Puerto Rico & Virgin Is. (EPSG:32161)
#> names       : level contour_value depth_label corridor_id buffer_distance nominal_corrid~  overlap_policy
#> type        : <num>         <num>       <num>       <int>           <num>           <num>           <chr>
#> values      :   -40           -40         -40           1               5              10 independent_ma~
#>                 -60           -60         -60           2               5              10 independent_ma~