angleSteps {celltrackR}

Angle between Two Steps

Description

Compute the angle between two steps in the dataset that occur at the same timepoint.

Usage

angleSteps(X, trackids, t, degrees = TRUE, quietly = FALSE)

Arguments

X

a tracks object

trackids

a vector of two indices specifying the tracks to get steps from, or a dataframe/matrix of two columns (where every row contains a pair of trackids to compute a step angle for)

t

the timepoint at which the steps should start, or a vector of timepoints if trackids is a matrix with multiple step pairs to compute angles for.

degrees

logical; should angle be returned in degrees instead of radians? (defaults to TRUE)

quietly

logical; should a warning be returned if one or both of the steps are missing in the data and the function returns NA?

Value

A single angle, or NA if the desired step is missing for one or both of the tracks. If trackids is a matrix with multiple step pairs to compute angles for, the output is a numeric vector of angles (or NA values).

See Also

distanceSteps to compute the distance between the step starting points, timePoints to list all timepoints in a dataset, and AngleAnalysis for other methods to compute angles and distances.

Examples

## Find the angle between the steps of the tracks with ids 1 and 2, at the 3rd
## timepoint in the dataset.
t <- timePoints( TCells )[3]
angleSteps( TCells, c("1","3"), t )

## Do this for multiple pairs and times at once: between cells 1 and 3 at the
## 3rd timepoint, and between 1 and 4 at the fourth timepoint.
pairs <- data.frame( cell1 = c("1","1"), cell2 = c("3","4"))
times <- timePoints(TCells)[3:4]
angleSteps( TCells, pairs, times )