Convert edge list to spatial object — edges_to

Converts an edge list to an sf spatial object of type LINESTRING with one row per edge.

edges_to_sf(edges, sites)

Arguments

edges: a data.frame with the following two columns: from (the first node of the edge) and to (the second node of the edge). The output of the functions create_edge_list() or append_edge_lists().
sites: an sf object of type POINT. A spatial object with coordinates of sites (nodes). Note that the first column must be the node labels.

Value

An sf spatial object of type LINESTRING where the number of rows correspond to the number of edges.

Examples

# Import Adour sites ----
path_to_file <- system.file("extdata", "adour_survey_sampling.csv", 
                            package = "chessboard")
adour_sites  <- read.csv(path_to_file)

# Select first location ----
adour_sites <- adour_sites[adour_sites$"location" == 1, ]

# Create node labels ----
adour_nodes <- create_node_labels(data     = adour_sites, 
                                  location = "location", 
                                  transect = "transect", 
                                  quadrat = "quadrat")

# Find edges with 1 degree of neighborhood (pawn method) ----
adour_edges <- create_edge_list(adour_nodes, method = "pawn", 
                                directed = TRUE)

# Convert sites to spatial POINT ----
adour_sites_sf <- sf::st_as_sf(adour_nodes, coords = 5:6, crs = "epsg:2154")

# Convert edges to spatial LINESTRING ----
edges_sf <- edges_to_sf(adour_edges, adour_sites_sf)
head(edges_sf)
#> Simple feature collection with 6 features and 2 fields
#> Geometry type: LINESTRING
#> Dimension:     XY
#> Bounding box:  xmin: 470209.3 ymin: 6221518 xmax: 476347 ymax: 6230758
#> Projected CRS: RGF93 v1 / Lambert-93
#>   from  to                       geometry
#> 1  1-1 1-2 LINESTRING (474036.9 622151...
#> 2  1-2 1-3 LINESTRING (473080 6223828,...
#> 3  1-3 1-4 LINESTRING (472123.1 622613...
#> 4  1-4 1-5 LINESTRING (471166.2 622844...
#> 5  2-1 2-2 LINESTRING (476347 6222475,...
#> 6  2-2 2-3 LINESTRING (475390.1 622478...

# Visualization ----
plot(sf::st_geometry(adour_sites_sf), pch = 19)
plot(sf::st_geometry(edges_sf), add = TRUE)



# Find edges with 1 degree of neighborhood (pawn and bishop methods) ----
adour_edges_1 <- create_edge_list(adour_nodes, method = "pawn", 
                                  directed = TRUE)
adour_edges_2 <- create_edge_list(adour_nodes, method = "bishop", 
                                  directed = TRUE)

# Append edges ----
adour_edges <- append_edge_lists(adour_edges_1, adour_edges_2)

# Convert sites to spatial POINT ----
adour_sites_sf <- sf::st_as_sf(adour_nodes, coords = 5:6, crs = "epsg:2154")

# Convert edges to spatial LINESTRING ----
edges_sf <- edges_to_sf(adour_edges, adour_sites_sf)
head(edges_sf)
#> Simple feature collection with 6 features and 2 fields
#> Geometry type: LINESTRING
#> Dimension:     XY
#> Bounding box:  xmin: 471166.2 ymin: 6221518 xmax: 475390.1 ymax: 6229405
#> Projected CRS: RGF93 v1 / Lambert-93
#>   from  to                       geometry
#> 1  1-1 1-2 LINESTRING (474036.9 622151...
#> 2  1-1 2-2 LINESTRING (474036.9 622151...
#> 3  1-2 1-3 LINESTRING (473080 6223828,...
#> 4  1-2 2-3 LINESTRING (473080 6223828,...
#> 5  1-3 1-4 LINESTRING (472123.1 622613...
#> 6  1-3 2-4 LINESTRING (472123.1 622613...

# Visualization ----
plot(sf::st_geometry(adour_sites_sf), pch = 19)
plot(sf::st_geometry(edges_sf), add = TRUE)