Jitter (add noise to) numeric movement data
jitter_weights.Rdjitter_weights() adds random noise (jitter) to a selected numeric column
in a movenet-format movement tibble. By default, the weight column is
selected.
Arguments
- data
A movenet-format movement tibble.
- range
A positive number, indicating the maximum amount of jitter to apply to the numeric data (see Details).
- column
Name of a single numeric column to jitter. By default this is the weight column (as specified in the loaded movement configurations).
Details
Requires that an appropriate movement config file is loaded, to correctly
identify the weight column in data.
The data in the selected column are modified by addition of an amount of
noise between -range and range, following a uniform distribution.
If this were to result in a data point becoming <= 0, the amount of jitter
for this data point is resampled, until the resulting data point becomes
positive. This is to capture that any movement in a livestock movement
database is assumed to have a positive weight (quantity of animals moved).
See also
base::jitter(), which this function is based on.
Other Privacy-enhancing functions:
anonymise(),
create_anonymisation_effect_analysis_report(),
jitter_dates(),
round_dates(),
round_weights()
Examples
# Set-up: Save movenet environment with current configurations
movenetenv <- movenet:::movenetenv
old_config <- movenetenv$options
# Load a movement config file
load_config(system.file("configurations", "ScotEID.yml",
package = "movenet"))
#> Successfully loaded config file: C:/Users/cboga/AppData/Local/Temp/Rtmp25xhub/temp_libpath11484970381d/movenet/configurations/ScotEID.yml
# Add random noise from -3 to +3 to movement weights
head(example_movement_data)
#> # A tibble: 6 x 5
#> departure_cph dest_cph departure_date qty_pigs movement_reference
#> <chr> <chr> <date> <dbl> <dbl>
#> 1 95/216/1100 19/818/9098 2019-02-08 97 304781
#> 2 69/196/5890 71/939/3228 2019-08-15 167 229759
#> 3 52/577/5349 82/501/8178 2019-09-15 115 36413
#> 4 39/103/5541 13/282/1763 2019-10-26 125 488616
#> 5 41/788/6464 57/418/6011 2019-10-17 109 581785
#> 6 69/393/9398 39/947/2201 2019-10-06 72 564911
moves_w_jittered_weights <- jitter_weights(example_movement_data, 3)
head(moves_w_jittered_weights)
#> # A tibble: 6 x 5
#> departure_cph dest_cph departure_date qty_pigs movement_reference
#> <chr> <chr> <date> <dbl> <dbl>
#> 1 95/216/1100 19/818/9098 2019-02-08 97.4 304781
#> 2 69/196/5890 71/939/3228 2019-08-15 169. 229759
#> 3 52/577/5349 82/501/8178 2019-09-15 115. 36413
#> 4 39/103/5541 13/282/1763 2019-10-26 126. 488616
#> 5 41/788/6464 57/418/6011 2019-10-17 107. 581785
#> 6 69/393/9398 39/947/2201 2019-10-06 69.8 564911
# Add random noise from -3 to +3 to movement reference numbers
moves_w_jittered_refs <- jitter_weights(example_movement_data,
range = 3,
column = "movement_reference")
head(moves_w_jittered_refs)
#> # A tibble: 6 x 5
#> departure_cph dest_cph departure_date qty_pigs movement_reference
#> <chr> <chr> <date> <dbl> <dbl>
#> 1 95/216/1100 19/818/9098 2019-02-08 97 304783.
#> 2 69/196/5890 71/939/3228 2019-08-15 167 229759.
#> 3 52/577/5349 82/501/8178 2019-09-15 115 36416.
#> 4 39/103/5541 13/282/1763 2019-10-26 125 488618.
#> 5 41/788/6464 57/418/6011 2019-10-17 109 581784.
#> 6 69/393/9398 39/947/2201 2019-10-06 72 564909.
# Clean-up: Reinstate previous configurations
movenetenv$options <- old_config
rm("old_config", "movenetenv", "moves_w_jittered_weights",
"moves_w_jittered_refs")