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Calculate the minimum distance linestring from an sf POINT object to nodes of a sf LINESTRING object

desplim_line_nearest_node.Rd

Calculate the minimum distance linestring connection from an sf POINT object to nodes of an sf LINESTRING object

Usage

desplim_line_nearest_node(
  input_nodes,
  input_lines,
  input_buildings = NULL,
  cast_substring = TRUE,
  combine_nodes = TRUE,
  ignore_equal = TRUE
)

Arguments

input_nodes

object of class sf with geometry type POINT or MULTIPOINT.

input_lines

object of class sf with geometry type LINESTRING or MULTILINESTRING.

input_buildings

optional object of class sf with geometry type POLYGON or MULTIPOLYGON to not be crossed.

cast_substring

logical; should the input linestring be cast to substring? Default is TRUE.

combine_nodes

logical; should the input nodes and nodes of the input lines be combined? Default is TRUE.

ignore_equal

logical; should output linestrings which are exactly equal to one or more elements in input_lines be ignored? Default is TRUE.

Value

An sf object of type LINESTRING containing the minimum distance linestrings from each node in input_nodes to nodes in input_lines or the combined set of input_nodes and nodes in input_lines.

Details

For each input node, the function computes the minimum distance to the chosen set of nodes and outputs the minimum distance linestrings. In cases where the minimum distance is zero, due to overlap of the input node and one or more nodes in input_lines, the second minimum distance linestring is computed. If input_nodes or input_lines contain geometries of type MULTIPOINT or MULTILINESTRING, they are converted to POINT and LINESTRING respectively before computing.

Examples

# Create nodes, lines and a building
crs <- 32632
line1 <- sf::st_linestring(rbind(c(0, 10), c(10, 10)))
line2 <- sf::st_linestring(rbind(c(10, 10), c(10, 0)))
lines_sf <- sf::st_as_sf(sf::st_sfc(line1, line2, crs = crs))

node1 <- sf::st_point(c(3, 6))
node2 <- sf::st_point(c(8, 4))
points_sf <- sf::st_as_sf(sf::st_sfc(node1, node2, crs = crs))

building_poly <- sf::st_polygon(list(rbind(
  c(1, 7),
  c(1, 9),
  c(4, 9),
  c(4, 7),
  c(1, 7)
)))
building_sf <- sf::st_as_sf(sf::st_sfc(building_poly, crs = crs))

# Compute connections with no building
connections_no_building <- desplim_line_nearest_node(points_sf, lines_sf)
print(connections_no_building)
#> Simple feature collection with 2 features and 0 fields
#> Geometry type: LINESTRING
#> Dimension:     XY
#> Bounding box:  xmin: 0 ymin: 0 xmax: 10 ymax: 10
#> Projected CRS: WGS 84 / UTM zone 32N
#>                 geometry
#> 1 LINESTRING (3 6, 0 10)
#> 2 LINESTRING (8 4, 10 0)

# Visualise
plot(sf::st_geometry(lines_sf), col = "black", lwd = 2)
plot(sf::st_geometry(points_sf), col = "slateblue3", pch = 16, cex = 2, add = TRUE)
plot(sf::st_geometry(connections_no_building), col = "olivedrab", lwd = 2, add = TRUE)


# Compute connections with building
connections_with_building <- desplim_line_nearest_node(
  input_nodes = points_sf,
  input_lines = lines_sf,
  input_buildings = building_sf
)
print(connections_with_building)
#> Simple feature collection with 1 feature and 0 fields
#> Geometry type: LINESTRING
#> Dimension:     XY
#> Bounding box:  xmin: 8 ymin: 0 xmax: 10 ymax: 4
#> Projected CRS: WGS 84 / UTM zone 32N
#>                 geometry
#> 1 LINESTRING (8 4, 10 0)

# Visualise
plot(sf::st_geometry(lines_sf), col = "black", lwd = 2)
plot(sf::st_geometry(building_sf), col = "tomato3", border = NA, add = TRUE)
plot(sf::st_geometry(points_sf), col = "blue", pch = 16, cex = 2, add = TRUE)
plot(sf::st_geometry(connections_with_building), col = "green", lwd = 2, add = TRUE)