Text, Arrow or Scale Bar in a Diagram
Create spatial objects that represent a text string, an arrow, or a yardstick (scale bar).
textstring(x, y, txt = NULL, ...)
onearrow(x0, y0, x1, y1, txt = NULL, ...)
yardstick(x0, y0, x1, y1, txt = NULL, ...)
- Coordinates where the text should be placed.
- Spatial coordinates of both ends of the arrow or yardstick.
x0can be a point pattern (class
"ppp") containing exactly two points, or a line segment pattern (class
"psp") consisting of exact
- The text to be displayed beside the line segment. Either a character string or an expression.
- Additional named arguments for plotting the object.
These commands create objects that represent components of a diagram:
textstringcreates an object that represents a string of text at a particular spatial location.
onearrowcreates an object that represents an arrow between two locations.
yardstickcreates an object that represents a scale bar: a line segment indicating the scale of the plot.
plot. See the help files for the plot methods
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
- An object of class
"diagramobj"which also belongs to one of the special classes
"yardstick". There are methods for
X <- rescale(swedishpines) plot(X, pch=16, main="") ys <- yardstick(as.psp(list(xmid=4, ymid=0.5, length=1, angle=0), window=Window(X)), txt="1 m") plot(ys, angle=90)