calc_mcp {aspace} | R Documentation |
This function computes the Minimum Convex Polygon (MCP) from a set of points. The MCP is the minimum area polygon containing a set of point locations.
calc_mcp(id=1, points = activities, filename="MCP_Output.txt", verbose = FALSE, pct = 100)
id |
Provide a unique integer to identify an MCP from others that you may construct with other data points |
points |
Two-column matrix or data frame of point coordinates |
filename |
A character name for an ASCII output file |
verbose |
Boolean: set to TRUE if extended processing feedback is wanted |
pct |
Integer 0 <= pct <=100, the percentage of the MCP for which area is provided |
This function is most powerful when used repetitively within a loop to compute the MCP for subsets of points stored in a large data table.
The returned result is a list:
MCP.area |
The area of the MCP in square kilometers |
MCP.pct |
The desired percentage of the MCP for which the area is computed |
MCP.coords |
A matrix containing MCP vertices. Each row represents a unique point, the first column contains x-coordinates, and the second, y-coordinates |
Results are stored in the r.MCP object (required for graphical visualization using plot_mcp). This function can be used on its own (once) or repetitively in a loop to process grouped point data stored in a larger table. When used repetitively, be sure to increment the id parameter to ensure that each MCP has a unique identifier. The output ASCII coordinate file can be further processed using the makeshapes function to generate an ESRI Shapefile for MCP polygons.
Randy Bui, Ron N. Buliung, Tarmo K. Remmel
Builds upon MCP functions available in the adehabitat package
plot_mcp
,
mcp
,
calc_sdd
,
calc_sde
,
calc_box
,
makeshapes
calc_mcp(id=1, points = activities, filename="MCP_Output.txt", verbose = FALSE, pct = 100)