triangulate: Estimate location of a signal from tracking data

In henry-dang/radiotrack: Methods for Triangulation in Wildlife Radio-Telemetry Studies

Description

This function uses tracking data to compute the locaton of a radiotransmitter using either the maximum likelihood estimator, Huber, or Andrews method, as specified by the user. The user will need to also specify the variable(s) that the function will use to group the tracking data and perform calculations on.

A dataframe containing the X- and Y-Coordinates for the location of the radiotransmitter will be returned, along with the group identifier(s) and number of iterations. If the function fails to compute a result for a group, an error message will be displayed in the X- and Y-Coordinate columns of the returned dataframe.

Usage

triangulate(df, x, y, bearings, group, method,
    iterations, threshold)

Arguments

df	Dataframe
x	Name of the X-coordinate variable, as a string.
y	Name of the Y-coordinate variable, as a string.
bearings	Name of the bearings variable, as a string.
group	Name(s) of the unique identifer or combinations of identifers to split dataframe by, as strings.
method	Method (mle, huber, andrews) used to perform calculations. Default is mle.
iterations	Maximum number of iterations to perform for each set of calculations before aborting. Default is 999.
threshold	Numeric specifying the precision of the calculations. Default is 0.0001.

References

Lenth, R.V. (1981). On Finding the Source of a Signal. Technometrics, 23(2), 149-154.

Examples

## Not run: 
tracking <- data.frame(
  "Date" = c(rep(1/1/2018, 3), rep(1/2/2018, 3),
  rep(1/1/2018, 3), rep(1/2/2018, 3)),
  "Triangulation.Series" = c(rep(1, 6), rep(2, 6)),
  "X.Coordinate" = c(-103.099, -103.098, -103.098, -103.080,
                     -103.080, -103.080, -99.874, -99.874,
                     -99.867, -99.873, -99.867, -99.874),
  "Y.Coordinate" = c(rep(33.774, 2), 33.775, 33.795, 33.796,
                     33.795, 36.506, 36.500, rep(36.5077, 3),
                     36.5042),
  "Bearings" = c(322, 296, 290, 69, 95, 51, 137, 51, 215,
                 97, 220, 50))

results <- triangulate(
  df = tracking,
  x = "X.Coordinate",
  y = "Y.Coordinate",
  bearings = "Bearings",
  groupp = .(Date, Triangulation.Series))
)

## End(Not run)

henry-dang/radiotrack documentation built on June 1, 2019, 10:16 p.m.