viewscape (version 2.0.2)

calculate_feature: calculate_feature

Description

The calculate_feature function is designed to extract specific feature-related information within a viewshed. It allows you to compute the proportion of the feature that is present in the viewshed.

Usage

calculate_feature(viewshed, feature, type, exclude_value)

Value

Numeric. The canopy area in the viewshed.

Arguments

viewshed

Viewshed object.

feature

Raster. Land cover or land use

type

Numeric. The input type of land cover raster. type=1: percentage raster (that represents the percentage of area in each cell). type=2: binary raster (that only uses two values to represent whether the feature exists in each cell).

exclude_value

Numeric. the value of those cells need to be excluded in the analysis. If type = 2, exclude_value is reqired.

Examples

library(viewscape)
# Load a viewpoint
test_viewpoint <- sf::read_sf(system.file("test_viewpoint.shp", package = "viewscape"))
# load dsm raster
dsm <- terra::rast(system.file("test_dsm.tif", package ="viewscape"))
#Compute viewshed
viewshed <- viewscape::compute_viewshed(dsm = dsm,
                                        viewpoints = test_viewpoint,
                                        offset_viewpoint = 6)
# load canopy raster
test_canopy <- terra::rast(system.file("test_canopy.tif",
                                       package ="viewscape"))
# calculate the percentage of canopy coverage
test_canopy_proportion <- viewscape::calculate_feature(viewshed = viewshed,
                                                       feature = test_canopy,
                                                       type = 2,
                                                       exclude_value = 0)