Get cell tracks from a data.frame. Data are expected to be organized as
follows.
One column contains a track identifier, which can be numeric or a string, and
determines which points belong to the same track.
Another column is expected to contain a time index or a time period (e.g. number of
seconds elapsed since the beginning of the track, or since the beginning of the
experiment). Input of dates is not (yet) supported, as absolute time information is
frequently not available.
Further columns contain the spatial coordinates. If there are three or less spatial
coordinates, their names will by "x", "y", and "z"
(depending on whether the tracks are 1D, 2D or 3D). If there are four or more spatial
coordinates, their names will be "x1", "x2", and so on.
The names or indices of these columns in the data.frame are given using the
corresponding parameters (see below). Names and indices can be mixed, e.g. you can
specify id.column="Parent" and pos.columns=1:3
# S3 method for data.frame
as.tracks(
x,
id.column = 1,
time.column = 2,
pos.columns = 3:ncol(x),
scale.t = 1,
scale.pos = 1,
...
)A tracks object.
the data frame to be coerced to a tracks object.
index or name of the column that contains the track ID.
index or name of the column that contains elapsed time.
vector containing indices or names of the columns that contain
the spatial coordinates. If this vector has two entries and the second entry is NA,
e.g. c('x',NA) or c(5,NA) then all columns from the indicated column
to the last column are used. This is useful when reading files where the exact number
of spatial dimensions is not known beforehand.
a value by which to multiply each time point. Useful for changing units, or for specifying the time between positions if this is not contained in the file itself.
a value, or a vector of values, by which to multiply each spatial position. Useful for changing units.
further arguments to be passed to read.csv, for instance
sep="\t" can be useful for tab-separated files.