track.gradinfo {emuR} | R Documentation |
Calculate gradient summary information for trackdata
Description
Calculates a number of summary measures for a trackdata object: duration, start and end data points, delta values and slope.
Usage
track.gradinfo(trackdata)
Arguments
trackdata |
An Emu trackdata object as returned by
|
Details
track.gradinfo
calculates a number of summary measure for the
segments within a trackdata object. These are useful for data such as
kinematic measures where segments might correspond to articulatory
movements etc.
Measures returned are: duration, start and end data values (ie. the first and last rows of data for each segment), delta (the difference between the first and last rows of data) and slope (delta divided by the duration).
Value
A data frame with one row per segment and columns:
duration |
Segment |
startN |
The starting value for each segment (start1 is the starting value for the first column) |
endN |
The ending value for each segment |
deltaN |
The delta value for each segment |
slopeN |
The slope value for each segment |
Since the result is a data frame, the columns can be referred to by name
(result$duration
) or as matrix columns (result[,1]
).
Author(s)
Steve Cassidy
See Also
Examples
data(vowlax)
segs = vowlax
## fm has 4 columns
data.fm <-vowlax.fdat
## F0 has one
data.F0 <- vowlax.fund
## info.fm will have duration, 4xstart, 4xend, 4xdelta, 4xslope
info.fm <- track.gradinfo(data.fm)
## this should be true
ncol(info.fm) == 1+4+4+4+4
## info.F0 will have one of each
info.F0 <- track.gradinfo(data.F0)
## this should be true
ncol(info.F0) == 1+1+1+1+1
## plot the durations vs delta of the first formant
plot(info.F0$duration, info.fm$delta1, type="n", xlab="Duration", ylab="Delta")
text(info.fm$duration, info.fm$delta1, labels=label(segs))
## extract just the delta values from the formant info
## You need to eyeball the data to work out which columns to select
delta.fm <- info.fm[,10:13]