R: Text, Arrow or Scale Bar in a Diagram

yardstick {spatstat} | R Documentation

## Text, Arrow or Scale Bar in a Diagram

### Description

Create spatial objects that represent a text string, an arrow, or a yardstick (scale bar).

### Usage

    textstring(x, y, txt = NULL, ...)

    onearrow(x0, y0, x1, y1, txt = NULL, ...)

    yardstick(x0, y0, x1, y1, txt = NULL, ...)

### Arguments

`x,y` | Coordinates where the text should be placed.
`x0,y0,x1,y1` | Spatial coordinates of both ends of the arrow or yardstick. Alternatively `x0` can be a point pattern (class `"ppp"`) containing exactly two points, or a line segment pattern (class `"psp"`) consisting of exactly one line segment.
`txt` | The text to be displayed beside the line segment. Either a character string or an expression.
`...` | Additional named arguments for plotting the object.

### Details

These commands create objects that represent components of a diagram:

- `textstring` creates an object that represents a string of text at a particular spatial location.

- `onearrow` creates an object that represents an arrow between two locations.

- `yardstick` creates an object that represents a scale bar: a line segment indicating the scale of the plot.

To display the relevant object, it should be plotted, using `plot`. See the help files for the plot methods `plot.textstring`, `plot.onearrow` and `plot.yardstick`.

These objects are designed to be included as components in a `layered` object or a `solist`. This makes it possible to build up a diagram consisting of many spatial objects, and to annotate the diagram with arrows, text and so on, so that ultimately the entire diagram is plotted using `plot`.

### Value

An object of class `"diagramobj"` which also belongs to one of the special classes `"textstring"`, `"onearrow"` or `"yardstick"`. There are methods for `plot`, `print`, `"["` and `shift`.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.

### See Also

`plot.textstring`, `plot.onearrow`, `plot.yardstick`.

### Examples

      X <- rescale(swedishpines)
      plot(X, pch=16, main="")
      yd <- yardstick(0,0,1,1, "diagonal")
      yy <- yardstick(X[1:2])
      ys <- yardstick(as.psp(list(xmid=4, ymid=0.5, length=1, angle=0),
                             window=Window(X)),
                      txt="1 m")
      ys
      plot(ys, angle=90)
      scalardilate(ys, 2)

[Package spatstat version 1.63-3 Index]