Running examples in ‘amt-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: steps
> ### Title: Functions to create and work with steps
> ### Aliases: steps direction_abs direction_abs.track_xy direction_rel
> ###   direction_rel.track_xy step_lengths step_lengths.track_xy
> ###   steps_by_burst steps_by_burst.track_xyt steps steps.track_xy
> ###   steps.track_xyt
> 
> ### ** Examples
> 
> 
> 
> # Absolute directions
> 
> xy <- data_frame(
+   x = c(1, 4, 8, 8, 12, 8, 0, 0, 4, 2),
+   y = c(0, 0, 0, 8, 12, 12, 12, 8, 4, 2))
> trk <- mk_track(xy, x, y)
.t missing, creating `track_xy`.
> 
> # append last
> direction_abs(trk, append_last = TRUE)
 [1]    0    0   90   45  180  180  -90  -45 -135   NA
> direction_abs(trk, append_last = FALSE)
[1]    0    0   90   45  180  180  -90  -45 -135
> 
> # degrees
> direction_abs(trk, degrees = FALSE)
 [1]  0.0000000  0.0000000  1.5707963  0.7853982  3.1415927  3.1415927
 [7] -1.5707963 -0.7853982 -2.3561945         NA
> direction_abs(trk, degrees = TRUE)
 [1]    0    0   90   45  180  180  -90  -45 -135   NA
> 
> # full circle or not
> direction_abs(trk, degrees = TRUE, full_circle = TRUE)
 [1]   0   0  90  45 180 180 270 315 225  NA
> direction_abs(trk, degrees = TRUE, full_circle = FALSE)
 [1]    0    0   90   45  180  180  -90  -45 -135   NA
> 
> # direction of 0
> direction_abs(trk, full_circle = TRUE, zero_dir = "N")
 [1] 270 270   0 315  90  90 180 225 135  NA
> direction_abs(trk, full_circle = TRUE, zero_dir = "E")
 [1]   0   0  90  45 180 180 270 315 225  NA
> direction_abs(trk, full_circle = TRUE, zero_dir = "S")
 [1]  90  90 180 135 270 270   0  45 315  NA
> direction_abs(trk, full_circle = TRUE, zero_dir = "W")
 [1] 180 180 270 225   0   0  90 135  45  NA
> 
> # clockwise or not
> direction_abs(trk, full_circle = TRUE, zero_dir = "N", clockwise = FALSE)
 [1] 270 270   0 315  90  90 180 225 135  NA
> direction_abs(trk, full_circle = TRUE, zero_dir = "N", clockwise = TRUE)
 [1]  90  90   0  45 270 270 180 135 225  NA
> 
> # Bearing (i.e. azimuth): only for lon/lat
> direction_abs(trk, full_circle = FALSE, zero_dir = "N", lonlat = FALSE, clockwise = TRUE)
 [1]   90   90    0   45  -90  -90  180  135 -135   NA
> direction_abs(trk, full_circle = FALSE, zero_dir = "N", lonlat = TRUE, clockwise = TRUE)
 [1]   90.00000   90.00000    0.00000   44.41780  -89.58401  -89.16705
 [7]  180.00000  134.74039 -134.79070         NA
> 
> # How do results compare to other packages
> # adehabitatLT
> df <- adehabitatLT::as.ltraj(data.frame(x = xy$x, y = xy$y), typeII = FALSE, id = 1)
> df[[1]]$abs.angle
 [1]  0.0000000  0.0000000  1.5707963  0.7853982  3.1415927  3.1415927
 [7] -1.5707963 -0.7853982 -2.3561945         NA
> amt::direction_abs(trk, degrees = FALSE, full_circle = FALSE)
 [1]  0.0000000  0.0000000  1.5707963  0.7853982  3.1415927  3.1415927
 [7] -1.5707963 -0.7853982 -2.3561945         NA
> 
> # bcpa
> df <- bcpa::MakeTrack(xy$x, xy$y, lubridate::now() +  lubridate::hours(1:10))
> bcpa::GetVT(df)$Phi
[1]  0.0000000  1.5707963  0.7853982  3.1415927  3.1415927 -1.5707963 -0.7853982
[8] -2.3561945
> direction_abs(trk, degrees = FALSE, full_circle = FALSE, append_last = FALSE)
[1]  0.0000000  0.0000000  1.5707963  0.7853982  3.1415927  3.1415927 -1.5707963
[8] -0.7853982 -2.3561945
> 
> # move
> m <- move::move(xy$x, xy$y, lubridate::now() + lubridate::hours(1:10),
+  proj = sp::CRS("+init=epsg:4326"))
Error in validityMethod(as(object, superClass)) : 
  There are NA timestamps records
Calls: <Anonymous> ... validObject -> anyStrings -> isTRUE -> validityMethod
Execution halted