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

perspPoints {spatstat} | R Documentation

## 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))

### 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.

### 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

Same as the return value from `points` or `segments`.

### 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

`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")

[Package spatstat version 1.54-0 Index]