perspPoints
Draw Points or Lines on a Surface Viewed in Perspective
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))
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
whenZ
was plotted.- …
Graphical arguments passed to
points
,lines
orsegments
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"
) andy0,x1,y1
can beNULL
.- nlevels
Number of contour levels
- levels
Vector of heights of contours.
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.
Value
See Also
Examples
# NOT RUN {
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")
# }