Create concentric circles around the reference point — dc_concentric

Create concentric circles around the reference point, using the results of the dc_move_from_reference_point.

Usage

dc_concentric_circles(
  positioning_result,
  steps = list(30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360)
)

Arguments

positioning_result: The object returned by the dc_move_from_reference_point function.
steps: The steps (in the unit of the durations used ine the dc_move_from_reference_point function) at which creating the circles.

Value

A sf LINESTRING object

Examples

library(sf)

# Read source points
source_pts <- st_read(
  dsn = system.file("gpkg/data-prefecture.gpkg", package = "distanamo"),
  layer = "prefecture", quiet = TRUE
)

# Read the background layer to deform
background_layer <- st_read(
  dsn = system.file("gpkg/data-prefecture.gpkg", package = "distanamo"),
  layer = "departement", quiet = TRUE
)

durations_mat <- read.csv(system.file("csv/mat.csv", package = "distanamo"), row.names = 1)
dur <- durations_mat["CAEN", ]

source_pts$durations <- as.double(dur)

ref_point <- subset(source_pts, source_pts$NOM_COM == "CAEN")
other_points <- subset(source_pts, !source_pts$NOM_COM == "CAEN")

# Generate position from durations between the reference point
# and the other points
positioning_result <- dc_move_from_reference_point(
  reference_point = ref_point,
  other_points = other_points,
  duration_col_name = "durations",
  factor = 1
)

# Create the interpolation grid
igrid <- dc_create(
  source_points = positioning_result$source_points,
  image_points = positioning_result$image_points,
  precision = 2.0,
  bbox = st_bbox(background_layer)
)

# Use the positioning result to create concentric circles
# every 60-minutes
circles <- dc_concentric_circles(
  positioning_result,
  c(60, 120, 180, 240, 300, 360, 420, 480, 540, 600, 660, 720)
)

# Deform the background layer
background_deformed <- dc_interpolate(
  interpolation_grid = igrid,
  layer_to_deform = background_layer
)