Package 'CityShadeMapper'

Generate height raster from LiDAR data

Description

Generate height raster from LiDAR data

Usage

calc_heights_from_lidar(
  las = NULL,
  res = 1,
  ground = FALSE,
  thresholds = c(0, 2, 5, 10, 20),
  filename = NULL,
  ...
)

Arguments

las	LiDAR data (a lidR::LAS-class() or lidR::LAScatalog-class() object).
res	Spatial resolution of the raster
ground	Logical. Calculate ground height in addition to canopy/roof heights?
thresholds	Set of height thresholds (see lidR::dsm_pitfree()).
filename	Character. Output filename. Note that if a file already exists with that name, it will be overwritten.
...	further arguments to lidR::pitfree()

Value

SpatRaster with height data

Examples

## Not run: 
heights <- calc_heights_from_lidar(PlazaNueva())

## End(Not run)

---

Calculate shaded route

Description

Calculate shaded route

Usage

calc_shaded_route(origin = NULL, destination = NULL, shaderas = NULL)

Arguments

origin	A character vector describing an address, an sf or a SpatVector object.
destination	A character vector describing an address, an sf or a SpatVector object.
shaderas	Shade raster

Value

A SpatVector object with the optimal route

Examples

## Not run: 
shaderas <- terra::rast("/vsicurl/https://zenodo.org/record/7213637/files/m7_h13_ground.tif")
shade.route <- calc_shaded_route("Plaza Nueva, Sevilla", "Mateos Gago, Sevilla", shaderas)

library(leaflet)
leaflet(sf::st_as_sf(shade.route)) |>
  leaflet::addWMSTiles(baseUrl = "https://www.ign.es/wms-inspire/ign-base",
  layers = "IGNBaseTodo-nofondo") |>
  leaflet::addTiles(urlTemplate =
    "https://mapasdesombra.github.io/Sevilla-jul-ground/13/{z}/{x}/{y}.png",
  options = leaflet::tileOptions(minZoom = 15, maxZoom = 18, tms = TRUE, opacity = 0.4)) |>
  addPolylines(weight = 8, opacity = 0.8)


## End(Not run)

---

Single building example

Description

An example 9 x 9 meter SpatRaster with a 4 m tall building in the middle.

Usage

example_building()

Value

A SpatRaster.

---

Square example

Description

An example 100 x 100 meter SpatRaster with a 10 m tall rectangular wall and a 4-m tall tree in the middle.

Usage

example_square()

Value

A SpatRaster.

---

Single tree example

Description

An example 9 x 9 meter SpatRaster with a 4 m tall tree in the middle.

Usage

example_tree()

Value

A SpatRaster.

---

Get sun position

Description

Get sun position (declination, elevation, and azimuth) for a given day and time.

Usage

get_sun_position(
  lon = NULL,
  lat = NULL,
  date = NULL,
  hour = NULL,
  omit.nights = TRUE
)

Arguments

lon	Longitude (numeric value between -180 and 180)
lat	Latitude (numeric value between -90 and 90)
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).
omit.nights	Logical. If TRUE, sun positions will only be returned when it is daytime (i.e. nighttimes will be omitted)

Value

A data frame with solar elevation and azimuth per hour as returned by solartime::computeSunPositionDoyHour() but converted to degrees rather than radians.

Examples

sunpos <- get_sun_position(lon = -5.99, lat = 37.39, date = "2021-02-19", hour = 15)
sunpos <- get_sun_position(lon = -5.99, lat = 37.39,
date = c("2021-02-19", "2022-08-05"), hour = 10:14)

---

Make leaflet shade map

Description

Make leaflet shade map

Usage

leaflet_shademap(
  url.canopy = NULL,
  url.ground = NULL,
  url.cog = NULL,
  band = 1,
  satellite = FALSE,
  opacity = 0.5
)

Arguments

url.canopy	Character. Url pointing to shade tiles at the canopy level.
url.ground	Character. Url pointing to shade tiles at the ground level.
url.cog	Character. Url pointing to a cloud-optimised geotiff (starting with 'https://'). The COG raster must have EPSG:4326 projection. Currently not implemented.
band	Numeric. Band to show in multilayer rasters (only for COG).
satellite	Logical. Add satellite images as another layer to the map?
opacity	Numeric between 0 and 1. Opacity of the shade layer.

Value

A leaflet map

Examples

## Not run: 
leaflet_shademap(url.canopy = "https://mapasdesombra.github.io/Sevilla-jul-canopy/11/{z}/{x}/{y}.png")

## End(Not run)

---

Calculate shade map

Description

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

## Not run: 
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)


## End(Not run)

---

Calculate shade map at the ground level

Description

Calculate shade map at the ground level

Usage

make_shademap_ground(shademap.canopy = NULL, cover.ras = NULL, filename = NULL)

Arguments

shademap.canopy	A SpatRaster with the illumination at the canopy level, made with make_shademap().
cover.ras	A SpatRaster containing cover classes (ground, vegetation, buildings...). See rasterize_lidar_cover_class().
filename	Character. Output filename. Note that if a file already exists with that name, it will be overwritten.

Value

A (possibly multilayer) SpatRaster object with the intensity of illumination at the ground level

Examples

## Not run: 
lidar <- read_lidar(system.file("extdata", "PlazaNueva.laz", package = "CityShadeMapper"))
cover.ras <- rasterize_lidar_cover_class(lidar)
shaderas.canopy <- make_shademap(heights, date = "2022-10-15", hour = 13)
shaderas.ground <- make_shademap_ground(shaderas.canopy, cover.ras)

## Alternatively, call make_shademap directly:
heights <- calc_heights_from_lidar(lidar)
shaderas.ground <- make_shademap(heights, date = "2022-10-15", hour = 13,
  type = "ground", cover.ras = cover.ras)

## End(Not run)

---

Plaza Nueva LiDAR data

Description

LiDAR data of Plaza Nueva in Sevilla, Spain. Data provided by LiDAR-PNOA 2018 CC-BY 4.0 scne.es.

Usage

PlazaNueva()

Value

A LAScatalog.

---

Plot shade map

Description

Plot shade map

Usage

plot_shademap(shade.ras = NULL, legend = TRUE, animate = FALSE, ...)

Arguments

shade.ras	A terra::SpatRaster() object with shade intensity, as produced by make_shademap().
legend	Logical. Show legend?
animate	Logical. Show animation of all the shade.ras layers?
...	Further arguments to terra::plot(), or to terra::animate() if animate is TRUE.

Value

A static or animated plot.

---

Get raster of cover classification from lidar points

Description

Get raster of cover classification from lidar points

Usage

rasterize_lidar_cover_class(
  las = NULL,
  res = 1,
  fill.holes = TRUE,
  filename = NULL
)

Arguments

las	A lidR::LAScatalog-class() object, or a character vector with paths to LAS/LAZ objects.
res	Resolution of the resulting raster.
fill.holes	Logical. Try to fill holes in lidar point classification.
filename	Character. Output filename. Note that if a file already exists with that name, it will be overwritten.

Value

A SpatRaster with the classification of cover types: 2 = ground (including low vegetation < 1m) 4 = high vegetation (> 1m) 6 = buildings 9 = water and NA values. Note that points classified as bridges (class 17) will be reclassified as ground.

Examples

## Not run: 
pza <- system.file("extdata", "PlazaNueva.laz", package = "CityShadeMapper")
pza.cover <- rasterize_lidar_cover_class(pza)

## End(Not run)

---

Read LiDAR data

Description

Read LiDAR data

Usage

read_lidar(folder = NULL, select = "xyz", filter = "-drop_class 7", ...)

Arguments

folder	Character. Path to folder containing las/laz files. Can also be a vector of file paths.
select	Character. Point attributes to read from the las/laz files. Use select = "*" to read all attributes. Default is "xyz" to save memory. See lidR::readLAS() for more details.
filter	Character. Optional. Use if you want to filter out some data points. For example, we could filter out noisy data points (class = 7) using filter = "-drop_class 7". Use filter = "" to read all data points.
...	Further arguments for lidR::readLAScatalog().

Value

LAScatalog object with LiDAR data

Examples

## Not run: 
las <- system.file("extdata", "PlazaNueva.laz", package = "CityShadeMapper")
lidar <- read_lidar(las)

## End(Not run)

---