This function generates points of natural origin around existent points by sampling their distance from the original propagule from a user-defined dispersal kernel (as set in function SDS(), the output of which is to be entered in this function as argument 'Delta'.
NPG(PresLoc, N, Deltas, year)data frame with coordinates of sighting locations. Column 2 must be 'y' (latitude on a projected coordinate system with meters as distance unit of measure) and column 3 must be 'x' (longitude on a projected coordinate system with meters as distance unit of measure).
total number of points to generate.
y and x shifts as generated from function SDS(). This function samples distance and angle of new points form existing ones from this argument.
the year lable to attach to the generated points
data frame of combined source ('PresLoc' argument) and new locations.