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Calculate shade map

Source: R/make_shademap.R
make_shademap.Rd

Calculate shade raster for given dates and hours

Usage

make_shademap(
  height.ras = NULL,
  date = NULL,
  hour = NULL,
  type = c("canopy", "ground"),
  cover.ras = NULL,
  zscale = 1,
  omit.nights = TRUE,
  filename = NULL,
  ...
)

Arguments

height.ras

A terra::SpatRaster() with heights data. Note height.ras must have a well defined crs (see terra::crs()).

date

A Date object or character giving the date in YYYY-MM-DD format (e.g. "2021-02-19"). Can be a vector too, e.g. c("2021-02-19", "2021-08-04"). Note different years have no effect on sun position calculations.

hour

Hour of the day. Integer number (or numeric vector) between 0 and 23 (both included).

type

Character. Either 'canopy' to get illumination at the canopy/roof level, or 'ground' to get illumination at the ground level (i.e. for pedestrians).

cover.ras

A SpatRaster containing cover classes (ground, vegetation, buildings...). See rasterize_lidar_cover_class().

zscale

Default 1. The ratio between the x and y spacing (which are assumed to be equal) and the z axis. For example, if the elevation is in units of meters and the grid values are separated by 10 meters, zscale would be 10.

omit.nights

Logical. If TRUE, sun positions will only be returned when it is daytime (i.e. nighttimes will be omitted)

filename

Character. Output filename. Note that if a file already exists with that name, it will be overwritten.

...

further arguments to rayshader::ray_shade()

Value

A (possibly multilayer) SpatRaster object with the intensity of illumination at each pixel for every date and time

Examples

if (FALSE) {
lidar <- PlazaNueva()
heights <- calc_heights_from_lidar(lidar)
shaderas <- make_shademap(heights, date = "2022-10-15", hour = 13)
plot_shademap(shaderas, smooth = TRUE)
shaderas <- make_shademap(heights, date = "2022-10-15", hour = 8:20)
plot_shademap(shaderas, animate = TRUE, smooth = TRUE)
shaderas <- make_shademap(heights, date = "2022-07-15", hour = 8:21)
plot_shademap(shaderas, animate = TRUE, smooth = TRUE)
shaderas <- make_shademap(heights, date = c("2022-07-15", "2022-10-15"), hour = 13)
plot_shademap(shaderas, legend = FALSE)

## Ground-level shade maps require additional raster with cover classes
lidar <- read_lidar(system.file("extdata", "PlazaNueva.laz", package = "CityShadeMapper"))
cover.ras <- rasterize_lidar_cover_class(lidar)
shaderas <- make_shademap(heights, date = "2022-10-15", hour = 13,
  type = "ground", cover.ras = cover.ras)

}