Hands-On Geospatial Analysis with R and QGIS

G-function

G-function is a useful function for describing clustering in point patterns. In this process, the distance of the nearest neighbor for each event is calculated and then the cumulative distribution of the nearest neighbor distance is used to give the probability of an event occurring within a distance, d. We can use G-function in R using Gest(). We can get the range of estimates for d values using envelope(), which presents them as a shaded region. We'll also need to adjust for the events near the window as these points might not give an unbiased nearest-neighbor distance—what can also be given as an argument to envelope(). If the data is over the envelope or the shaded region, that would indicate clustering:

ppp_gf = envelope(ppp_object3, ...