spatstat (version 1.31-3)

persp.im: Perspective Plot of Pixel Image

Description

Displays a perspective plot of a pixel image.

Usage

## S3 method for class 'im':
persp(x, \dots, colmap=NULL)

Arguments

x

The pixel image to be plotted. An object of class "im" (see im.object).

...

Extra arguments passed to persp.default to control the display.

colmap

Optional data controlling the colour map. See Details.

Value

• Returns the 3D transformation matrix returned by persp.default.

Details

This is the persp method for the class "im".

The pixel image x must have real or integer values. These values are treated as heights of a surface, and the surface is displayed as a perspective plot on the current plot device, using equal scales on the x and y axes.

The optional argument colmap gives an easy way to display different altitudes in different colours (if this is what you want).

• Ifcolmapis a colour map (object of class"colourmap", created by the functioncolourmap) then this colour map will be used to associate altitudes with colours.
• Ifcolmapis a character vector, then the range of altitudes in the perspective plot will be divided intolength(colmap)intervals, and those parts of the surface which lie in a particular altitude range will be assigned the corresponding colour fromcolmap.
• Ifcolmapis a list with entriesbreaksandcol, thencolmap$breaksdetermines the breakpoints of the altitude intervals, andcolmap$colprovides the corresponding colours.

Graphical parameters controlling the perspective plot are passed through the ... arguments directly to the function persp.default. See the examples in persp.default or in demo(persp).

See Also

im.object, plot.im, contour.im

Examples

# an image
   Z <- setcov(owin())
   persp(Z, colmap=terrain.colors(128))
   co <- colourmap(range=c(0,1), col=rainbow(128))
   persp(Z, colmap=co, axes=FALSE, shade=0.3)