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Summarize total area of land cover classes

Source: R/sum_landcover.R
sum_landcover.Rd

Summarize the area or number of pixels of each land cover class from a set of landscape rasters

Usage

sum_landcover(
  landscapes,
  mask = NULL,
  zones = NULL,
  pixel_area = 1,
  rollup = TRUE
)

Arguments

landscapes

Either a SpatRaster with one or more layers, or a character string giving the filepath to a directory containing one or more raster landscapes (e.g. scenarios) to be summarized.

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

zones

Optional SpatRaster or character string giving the filepath to a raster encoding zones within which pixel values should be summarized

pixel_area

Numeric value representing the area of each pixel; hectares preferred but any units may be provided; default is 1, resulting in a total count

rollup

Logical; whether or not riparian and managed wetland subclasses should be rolled up into a total area of riparian and managed wetlands, respectively. See Details.

Value

tibble

Details

This function will summarize the frequency of pixels of each land cover class in each landscape raster, either provided as a SpatRaster created by terra::rast() with one or more layers, or as a filepath to a directory containing one or more tif raster files to be summarized. This function is generally agnostic as to the names of the rasters and the land cover classes it expects, but it does expect the rasters to have unique names and to have land cover class levels defined (i.e., not just contain numeric codes; see terra::levels()). However, if rollup = TRUE (the default), riparian and managed wetland subclasses are expected to have names that begin with 'RIPARIAN_' or 'WETLAND_MANAGED_'. These subclasses will be summarized into a total area of 'RIPARIAN' and 'WETLAND_MANAGED' land cover classes.

This function relies on terra::freq() to summarize the total number of cells of each value within each raster and optionally each zone provided, which are then multiplied by pixel_area as an estimate of the total area of each land cover class in each landscape. The value for pixel_area can be provided in any units you prefer, but if this function is intended to produce areadat for use with sum_metrics(), we recommend using hectares to ensure alignment with the units in which metrics were estimated.

By default, the total area of each unique land cover class will be summarized for the entire raster provided, but optionally, the area can be subset by providing a mask and/or zones. A mask should be a single SpatRaster or filepath to a tif raster file that will be passed to terra::mask() to exclude any areas with NA values. In addition, zones should be a single SpatRaster or filepath to a tif raster file that will be passed to terra::zonal(). Values in zones should define two or more unique regions within which the area of each land cover class should be summarized, and the names of each region should be defined (see terra::levels()).

See also

sum_habitat(), sum_metrics()

Examples

# See vignette