tdtr {topdowntimeratio}

Perform Top-Down Time Ratio segmentation

Description

Perform Top-Down Time Ratio segmentation

Usage

tdtr(
  data,
  col_names = list(entity_id_col = "entity_id", timestamp_col = "timestamp", latitude_col
    = "lat", longitude_col = "lon"),
  group_col = "state_id",
  max_segs = 5000,
  n_segs = max_segs,
  max_error = 200,
  add_iterations = FALSE
)

Arguments

data

is a data.frame or data.table with timestamp, lat and lon

col_names

named list with existing column names for timestamp, latitude and longitude column (these are changed to 'timestamp', 'lat' and 'lon' respectively)

group_col

NULL for no grouping, or string column name representing a grouping in the data where initial segments will be drawn.

max_segs

with maximum number of segments allowed, default is 5000

n_segs

used to generate a specific number of segments

max_error

used as stopping criteria, default is 200

add_iterations

Add iterations to previous tdtr run

Value

data.table with segment information

Examples

df <- data.frame(person = rep(1, 12),
   time = c(1, 2, 4, 10, 14, 18, 20, 21, 24, 25, 28, 29),
   longitude = c(5.1299311, 5.129979, 5.129597, 5.130028, 5.130555, 5.131083,
           5.132101, 5.132704, 5.133326, 5.133904, 5.134746, 5.135613),
   lat = c(52.092839, 52.092827, 52.092571, 52.092292, 52.092076, 52.091821,
           52.091420, 52.091219, 52.091343, 52.091651, 52.092138, 52.092698))
# Generate segments under a max error of 100m
res100 <- tdtr(df,
     col_names = list(entity_id_col = "person",
                      timestamp_col = "time",
                      latitude_col = "lat",
                      longitude_col = "longitude"),
     group_col = NULL,
     max_error = 100)
# Generate segments under a max error of 30m
res30 <- tdtr(df,
     col_names = list(entity_id_col = "person",
                      timestamp_col = "time",
                      latitude_col = "lat",
                      longitude_col = "longitude"),
     group_col = NULL,
     max_error = 30)
plot(df$lon, df$lat)
segments(res100$seg_start_lon, res100$seg_start_lat,
         res100$seg_end_lon, res100$seg_end_lat, col = "blue")
segments(res30$seg_start_lon, res30$seg_start_lat,
         res30$seg_end_lon, res30$seg_end_lat, col = "red")