exercise_B

1 Exercise B

library(ggplot2)
library(readr)

pedestrian <- read_delim("data/pedestrian.csv", ",")
pedestrian$TrajID <- as.factor(pedestrian$TrajID)
 
ggplot(data = pedestrian, aes(E, N, colour = TrajID)) +
  facet_wrap(~ TrajID, ncol=3)+
  geom_point() +
  geom_path() +
  geom_point() +
  coord_fixed() +
  theme(legend.position = "bottom")

library(SimilarityMeasures)

traj_list <- split(pedestrian[, c("E", "N")], pedestrian$TrajID)
traj_mats <- lapply(traj_list, as.matrix)

dtw_vals <- sapply(2:6, function(i) {
  DTW(traj_mats[[1]], traj_mats[[i]])
})

frechet_vals <- sapply(2:6, function(i) {
  Frechet(traj_mats[[1]], traj_mats[[i]])
})

edit_vals <- sapply(2:6, function(i) {
  EditDist(traj_mats[[1]], traj_mats[[i]])
})

lcss_vals <- sapply(2:6, function(i) {
  LCSS(traj_mats[[1]], traj_mats[[i]],
       pointSpacing = 2,
       pointDistance = 3,
       errorMarg = 1)
})

results <- data.frame(
  Traj = 2:6,
  DTW = dtw_vals,
  Frechet = frechet_vals,
  EditDist = edit_vals,
  LCSS = lcss_vals
)

results

  Traj       DTW    Frechet EditDist LCSS
1    2  3650.025   28.54075       45    1
2    3 50785.511 2307.84366       47    1
3    4  5906.787 1069.22917       42    2
4    5  2178.411  717.98159       28    5
5    6  1152.718   38.96272       27    4

results_long <- reshape2::melt(results, id.vars = "Traj")
results_long$Traj <- as.factor(results_long$Traj)

ggplot(data = results_long, aes(Traj, value, fill = Traj)) +
  facet_wrap(~ variable, ncol=2, scales = "free_y")+
  geom_col()