```r
# clean street network
execGRASS(cmd = "v.clean", input = "london_streets", output = "streets_clean",
          tool = "break", flags = "overwrite")
# connect points with street network
execGRASS(cmd = "v.net", input = "streets_clean", output = "streets_points_con", 
          points = "points", operation = "connect", threshold = 0.001,
          flags = c("overwrite", "c"))
```