plot.im {spatstat} | R Documentation |
Plot a pixel image.
## S3 method for class 'im': plot(x, ..., col=NULL, ribbon=TRUE, ribsep=0.15, ribwid=0.05, ribn=1024)
x |
The pixel image to be plotted.
An object of class "im" (see im.object ).
|
... |
Extra arguments passed to image to control the plot.
|
col |
Colours representing the pixel values. A character vector representing colours. |
ribbon |
Logical flag indicating whether to display a ribbon showing the colour map. |
ribsep |
Factor controlling the space between the ribbon and the image. |
ribwid |
Factor controlling the width of the ribbon. |
ribn |
Number of different values to display in the ribbon. |
This is the plot
method for the class "im"
.
[It is also the image
method for "im"
.]
The pixel image x
is displayed on the current plot device,
using equal scales on the x
and y
axes.
If ribbon=TRUE
, a legend will be plotted at the right of the
image. The legend consists of a colour ribbon and an axis with tick-marks,
showing the correspondence between the pixel values and the colour map.
Arguments ribsep, ribwid, ribn
control the appearance of the
ribbon.
The width of the ribbon is ribwid
times the size of the pixel
image, where `size' means the larger of the width and the height.
The distance separating the ribbon and the image is ribsep
times
the size of the pixel image. The ribbon contains ribn
different numerical values, evenly spaced between the minimum and
maximum pixel values in the image x
, rendered according to
the chosen colour map.
The pixel values are displayed using the colours given in the
argument col
. The mapping of pixel values to colours is
determined as follows.
FALSE
and
TRUE
are mapped to the colours col[1]
and
col[2]
respectively.
The vector col
should have length 2.
levels(x)
are mapped to the entries of col
in order. The vector
col
should have the same length as levels(x)
.
x
is divided into n = length(col)
equal subintervals, which are mapped to the colours in col
.
(If col
was not specified, it defaults to a vector of 255
colours.)
Alternatively if the argument zlim
is given, it should be
a vector of length 2 specifying an interval of real numbers.
This interval will be used instead of the range of pixel
values. The interval from zlim[1]
to zlim[2]
will be
mapped to the colours in col
. This facility enables the user to
plot several images using a consistent colour map.
Alternatively if the argument breaks
is given, then this specifies
the endpoints of the subintervals that are mapped to each colour.
This is incompatible with zlim
.
The arguments col
and zlim
or breaks
are passed to the function image.default
.
For examples of the use of these arguments,
see image.default
.
Other graphical parameters controlling the display of both the pixel image
and the ribbon are passed through the ...
arguments
directly to the function image.default
.
To suppress the axis tick marks and labels, set axes=FALSE
.
none.
Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
im.object
,
contour.im
,
persp.im
,
image.default
,
spatstat.options
# an image Z <- setcov(owin()) plot(Z) plot(Z, col=terrain.colors(128), axes=FALSE)