Calculate gradient summary information for trackdata
Calculates a number of summary measures for a trackdata object: duration, start and end data points, delta values and slope.
track.gradinfo(trackdata)
trackdata |
An Emu trackdata object as returned by
|
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).
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$duration
) or as matrix columns (result[,1]
).
Steve Cassidy
data(vowlax) segs = vowlax ## fm has 4 columns data.fm <-vowlax.fdat ## F0 has one data.F0 <- vowlax.fund ## info.fm will have duration, 4xstart, 4xend, 4xdelta, 4xslope info.fm <- track.gradinfo(data.fm) ## this should be true ncol(info.fm) == 1+4+4+4+4 ## info.F0 will have one of each info.F0 <- track.gradinfo(data.F0) ## this should be true ncol(info.F0) == 1+1+1+1+1 ## plot the durations vs delta of the first formant plot(info.F0$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]
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