points.segmented: Points method for segmented objects
Description
Takes a fitted segmented object returned by segmented() and adds
on the current plot the joinpoints of the fitted broken-line relationships.
Usage
## S3 method for class 'segmented':
points(x, term, interc = TRUE, link = TRUE, rev.sgn=FALSE, ...)
Arguments
x
an object of class segmented.
term
the segmented variable of interest. It may be unspecified when there is a single segmented variable.
interc
If TRUE the computed joinpoints include the model intercept (if it exists).
link
when TRUE (default), the fitted joinpoints are plotted on the link scale
rev.sgn
when TRUE, the fitted joinpoints are plotted on the `minus' scale
of the current term variable. This is useful when a null-constraint
has been set on the last slope.
...
other graphics parameters to pass on to points() function.
Details
We call 'joinpoint' the plane point having as coordinates the breakpoint (on the x scale) and the fitted value of
the segmented relationship at that breakpoint (on the y scale). points.segmented() simply adds the fitted
joinpoints on the current plot. This could be useful to emphasize the changes of the piecewise linear relationship.