edge.creation: Creating graph edges
In gDefrag: Graph-Based Landscape De-Fragmentation

Description Usage Arguments Details Value Author(s) See Also Examples

View source: R/edge.creation.R

Generates the graph edges, connecting nodes that are the landscape polygons resulting from the landscape clip by the road network.

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edge.creation(nodes, land_polyg, min_length = 0, 
min_pol_area = 0, plot = TRUE, shape = FALSE, 
shape_name_edges = "shape_edges")

`nodes`	Output of the function `node.creation`.
`land_polyg`	SpatialPolygonsDataFrame loaded with readOGR function of the package `rgdal` (polygon shapefile).
`min_length`	Minimum length of the road segment to consider creating an edge representing it.
`min_pol_area`	Minimum area for a given polygon to be considered a node.
`plot`	Plot after running? (TRUE/FALSE).
`shape`	Create a shapefile with the edges (TRUE/FALSE).
`shape_name_edges`	Name of the edges shapefile to be created (without prioritization).

If shape = TRUE, this function produces one shapefile with edges without prioritization metrics.

The function returns a SpatialLinesDataFrame with the edges. The data table of this data frame has the following fields:

node_A - Node A Id.
node_B - Node B Id.
distance - Euclidean distance between nodes A and B (edge length).
x_node_A - Node A longitude.
y_node_A - Node A latitude.
x_node_B - Node B longitude.
y_node_A - Node A latitude.
raster_value_A - Average value of the underlying raster in the polygon represented by node A.
raster_value_B - Average value of the underlying raster in the polygon represented by node B.
road_ID - Id of the road represented by the edge.
road_length - Length of the road represented by the edge.

Frederico Mestre, Fernando Ascensao and A. Marcia Barbosa

node.creation

data(road_P)

out1 <- node.creation(land_polyg=road_P, value_col = "forest_sum", scale_nodes = 10, 
col_nodes = "pink", cex_labels = 0.7)

out2 <- edge.creation(nodes = out1, land_polyg = road_P, min_length = 0, 
min_pol_area = 0, plot = FALSE)