Usage
persp.gam(x, view=NULL, slice=list(), sizes=c(20,20), mask=FALSE, se=2,
theta=0, phi=15, r = sqrt(3), d = 1, scale = TRUE, expand = 1,
col = NULL, border = NULL, ltheta = -135, lphi = 45, shade = 0.75,
box = TRUE, axes = TRUE, nticks = 5, ticktype = "detailed",...)Arguments
x
a gam object, produced by gam()
view
a vector containing the names of the two covariates to be displayed on the
x and y dimensions of the plot.
slice
a named list of the values used for the covariates not directly displayed by
the diagram. Either in numbers or as functions of the two view parameters. Any
covariates not mentioned in the list will default to the mean of the gam's dat
sizes
The number of grid squares in each direction used for calculating the
plotted surface.
mask
If FALSE (default) the whole surface is displayed, otherwise those parts
of the surface far from all the datapoints are removed. Numeric values of mask
determine what is considered far. If mask is TRUE the maximum nearest
se
if positive meshs this many standard errors above (red) and below (green) the
main (grey) function surface are added to the plot. Zero, negative or FALSE values suppress production of these extra surfaces
theta
angle defining the azimuthal viewing direction.
phi
the colatitudeof the viewing direction.
r
the distance of the eyepoint from the centre of the plotting box.
d
a value which can be used to vary the strength of
the perspective transformation. Values of d greater
than 1 will lessen the perspective effect and values less
and 1 will exaggerate it.
scale
before viewing the x, y and z coordinates of the
points defining the surface are transformed to the interval
[0,1]. If scale is TRUE the x, y and z coordinates
are transformed separately. If scale is
expand
a expansion factor applied to the z
coordinates. Often used with 0 < expand < 1 to shrink the
plotting box in the z direction.
col
the color of the surface facets.
border
the color of the line drawn around the surface facets.
A value of NA will disable the drawing of borders. This is
sometimes useful when the surface is shaded.
ltheta
if finite values are specified for ltheta
and lphi, the surface is shaded as though it was being
illuminated from the direction specified by azimuth ltheta
and colatitude lphi.
shade
the shade at a surface facet is computed as
((1+d)/2)^shade, where d is the dot product of
a unit vector normal to the facet and a unit vector in the
direction of a light source. Values of shade close
box
should the bounding box for the surface be displayed.
The default is TRUE.
axes
should ticks and labels be added to the box. The
default is TRUE. If box is FALSE then no
ticks or labels are drawn.
nticks
the (approximate) number of tick marks to draw on the
axes. Has no effect if ticktype is "simple".
ticktype
character: "simple" draws just an arrow parallel to
the axis to indicate direction of increase; "detailed" draws normal
ticks as per 2D plots.