Returns additional columns for incoming and outcoming speed to the
data.table. Speed in metres per time interval. The time interval is dependent
on the units of the column specified in TIME.
Usage
atl_get_speed(
data,
tag = "tag",
x = "x",
y = "y",
time = "time",
type = c("in", "out")
)Arguments
- data
A dataframe or similar which must have the columns specified by
x,y, andtime.- tag
The tag ID.
- x
The x coordinate.
- y
The y coordinate.
- time
The timestamp in seconds since the UNIX epoch.
- type
The type of speed (incoming or outgoing) to return. Incoming speeds are specified by
type = "in", and outgoing speeds bytype = "out"or both c("in", "out").
Examples
library(tools4watlas)
library(data.table)
# Create example data with two tags
set.seed(123)
data <- data.table(
tag = rep(c("1000", "2000"), each = 5),
x = c(1, 3, 6, 10, 15, 2, 4, 7, 11, 16),
y = c(2, 5, 9, 14, 20, 3, 6, 10, 15, 21)
)
# Add a Unix timestamp column (randomized within a date range)
start_time <- as.numeric(as.POSIXct("2024-01-01 00:00:00", tz = "UTC"))
data[, time := start_time + sample(0:10000, .N, replace = TRUE)]
#> tag x y time
#> <char> <num> <num> <num>
#> 1: 1000 1 2 1704069662
#> 2: 1000 3 5 1704069710
#> 3: 1000 6 9 1704075917
#> 4: 1000 10 14 1704070185
#> 5: 1000 15 20 1704069041
#> 6: 2000 2 3 1704076533
#> 7: 2000 4 6 1704070570
#> 8: 2000 7 10 1704071960
#> 9: 2000 11 15 1704073945
#> 10: 2000 16 21 1704077018
data <- atl_get_speed(data,
tag = "tag",
x = "x",
y = "y",
time = "time",
type = c("in", "out")
)