node.creation: Creating graph nodes

In gDefrag: Graph-Based Landscape De-Fragmentation

Description

Generates the nodes that are the landscape polygons resulting from the landscape clip by infrastructure network.

Usage

node.creation(land_polyg, value_col, plot = TRUE, 
scale_nodes = 1, col_nodes = "deepskyblue4", cex_labels = 1, 
shape = FALSE, shape_name_nodes = "shape_nodes")

Arguments

land_polyg	SpatialPolygonsDataFrame loaded with readOGR function of the package rgdal (polygon shapefile).
value_col	Which column in the SpatialPolygonsDataFrame has the relevant information on the underlying raster. This information must be retrieved previously using a GIS, if the user wishes to use the method 'value' for prioritizing edges.
plot	Plot the output (TRUE/FALSE).
scale_nodes	Scaling factor to represent the nodes graphically.
col_nodes	Nodes colour.
cex_labels	Font size of the labels.
shape	Create a shapefile with the edges (TRUE/FALSE).
shape_name_nodes	Name of the nodes shapefile to be created (all nodes).

Details

If shape = TRUE, this function produces one shapefile with all the nodes.

Value

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

• X - Node latitude.

• Y - Node longitude.

• pol_value - Underlying raster value summed for each polygon.

• pol_area - Polygon area.

Author(s)

Frederico Mestre, Fernando Ascensao and A. Marcia Barbosa

See Also

edge.creation

Examples

data(road_P)

out1 <- node.creation(land_polyg = road_P, value_col = "forest_sum", 
scale_nodes = 10, col_nodes = "pink", cex_labels = 1)

gDefrag documentation built on Sept. 3, 2020, 1:07 a.m.