dynIdentify {TeachingDemos}

Interacively place labels for points in a plot

Description

These functions create a scatterplot of your points and place labels for the points on them. You can then use the mouse to click and drag the labels to new positions with a line stretching between the point and label.

Usage

dynIdentify(x, y, labels = seq_along(x),
  corners = cbind(c(-1, 0, 1, -1, 1, -1, 0, 1),
    c(1, 1, 1, 0, 0, -1, -1, -1)), ...)
TkIdentify(x, y, labels=seq_along(x), hscale=1.75, vscale=1.75,
  corners = cbind( c(-1,0,1,-1,1,-1,0,1), c(1,1,1,0,0,-1,-1,-1) ),...)

Arguments

x

x-values to plot

y

y-values to plot

labels

Labels for the points, defaults to a sequence of integers

corners

2 column matrix of locations where the line can attach to the label, see below

hscale, vscale

Scaling passed to tkrplot

...

Additional parameters passed to plot

Details

These functions create a scatterplot of the x and y points with the labels (from the argument above) plotted on top. You can then use the mouse to click and drag the labels to new locations. The Tk version shows the labels being dragged, dynIdentify does not show the labels being dragged, but the label will jump to the new location as soon as you release the mouse button.

The corners argument is a 2 column matrix that gives the allowable points at which the line from the point can attach to the label (so the line does not cover thelabel). The first column represents the x-coordinates and the 2nd column the y-coordinates. A 1 represents the right/top of the label, A -1 is the left/bottom and a 0 is the center. The default values allow attachments at the 4 corners and the centers of the 4 sides of the rectangle bounding the label.

Value

A list of lists with the coordinates of the final positions of the labels and the line ends.

Note

The dynIdentify function only works on windows, TkIdentify should work on any platform with tcltk.

Author(s)

Greg Snow, [e-mail]

See Also

identify

Examples

if(interactive()) {
  tmp <- TkIdentify(state.x77[,'Frost'], state.x77[,'Murder'],
  state.abb)
     ### now move the labels

     ### recreate the graph on the current device
  plot( state.x77[,'Frost'], state.x77[,'Murder'],
        xlab='Frost', ylab='Frost')
  text( tmp$labels$x, tmp$labels$y, state.abb )
  segments( state.x77[,'Frost'], state.x77[,'Murder'],
            tmp$lineends$x, tmp$lineends$y )
}