spatstat.geom (version 2.4-0)

perspPoints: Draw Points or Lines on a Surface Viewed in Perspective

Description

After a surface has been plotted in a perspective view using persp.im, these functions can be used to draw points or lines on the surface.

Usage

perspPoints(x, y=NULL, ..., Z, M)
perspLines(x, y = NULL, ..., Z, M)
perspSegments(x0, y0 = NULL, x1 = NULL, y1 = NULL, ..., Z, M)
perspContour(Z, M, ...,
             nlevels=10, levels=pretty(range(Z), nlevels))

Value

Same as the return value from

points

or segments.

Arguments

x,y

Spatial coordinates, acceptable to xy.coords, for the points or lines on the horizontal plane.

Z

Pixel image (object of class "im") specifying the surface heights.

M

Projection matrix returned from persp.im when Z was plotted.

...

Graphical arguments passed to points, lines or segments to control the drawing.

x0,y0,x1,y1

Spatial coordinates of the line segments, on the horizontal plane. Alternatively x0 can be a line segment pattern (object of class "psp") and y0,x1,y1 can be NULL.

nlevels

Number of contour levels

levels

Vector of heights of contours.

Author

Adrian Baddeley , Rolf Turner and Ege Rubak

Details

After a surface has been plotted in a perspective view, these functions can be used to draw points or lines on the surface.

The user should already have called persp.im in the form M <- persp(Z, visible=TRUE, ...) to display the perspective view of the surface Z.

Only points and lines which are visible from the viewer's standpoint will be drawn.

See Also

persp.im

Examples

  M <- persp(bei.extra$elev, colmap=terrain.colors(128),
             apron=TRUE, theta=-30, phi=20,
             zlab="Elevation", main="", 
             expand=6, visible=TRUE, shade=0.3)

  perspContour(bei.extra$elev, M=M, col="pink", nlevels=12)
  perspPoints(bei, Z=bei.extra$elev, M=M, pch=16, cex=0.3, col="chartreuse")