"plot"(x, ..., main, add=FALSE, clipwin=NULL, col=NULL, valuesAreColours=NULL, log=FALSE, ribbon=show.all, show.all=!add, ribside=c("right", "left", "bottom", "top"), ribsep=0.15, ribwid=0.05, ribn=1024, ribscale=1, ribargs=list(), colargs=list(), useRaster=NULL, workaround=FALSE, do.plot=TRUE)
"image"(x, ..., main, add=FALSE, clipwin=NULL, col=NULL, valuesAreColours=NULL, log=FALSE, ribbon=show.all, show.all=!add, ribside=c("right", "left", "bottom", "top"), ribsep=0.15, ribwid=0.05, ribn=1024, ribscale=1, ribargs=list(), colargs=list(), useRaster=NULL, workaround=FALSE, do.plot=TRUE)"im" (see im.object).
image.default
to control the plot. See Details.
add=TRUE)
or to initialise a new plot (add=FALSE, the default).
"owin").
Only this subset of the image will be displayed.
colourmap,
or a function as described under Details.
TRUE, the pixel values of x
are to be interpreted as colour values.
TRUE, the colour map will be
evenly-spaced on a logarithmic scale.
TRUE
for new plots and FALSE for added plots.
TRUE
for new plots and FALSE for added plots.
image.default and
axis
to control the display of the ribbon and its scale axis. These may override
the ... arguments.
col if it is a function.
image.default.
Images are plotted using a bitmap raster if useRaster=TRUE
or by drawing polygons if useRaster=FALSE.
Bitmap raster display tends to produce better results,
but is not supported on all graphics devices.
The default is to use bitmap raster display if it is supported.
do.plot=FALSE will simply return the
colour map and the bounding box that were chosen for the plot.
"colourmap".Also has an attribute "bbox" giving a bounding box
for the colour image (including the ribbon if present).
x are complex numbers,
they will be converted into four images containing the real and
imaginary parts and the modulus and argument,
and plotted side-by-side using plot.imlist.spatstat.options("monochrome") has been set to TRUE,
then the image will be plotted in greyscale.
The colours are converted to grey scale values using
to.grey.
The choice of colour map still has an effect, since it determines
the final grey scale values. Monochrome display can also be achieved by
setting the graphics device parameter colormodel="grey"
when starting a new graphics device, or in a call to
ps.options or pdf.options.image.default
and rasterImage explains that
errors may occur, or images may be rendered incorrectly, on some
devices, depending on the availability of colours and other
device-specific constraints. If the image is not displayed at all,
try setting useRaster=FALSE in the call to plot.im.
If the ribbon colours are not displayed, set
ribargs=list(useRaster=FALSE). Errors may occur on some graphics devices if the image is very
large. If this happens, try setting useRaster=FALSE in the
call to plot.im. The error message
useRaster=TRUE can only be used with a regular grid
means that the $x$ and $y$ coordinates of the pixels in the
image are not perfectly equally spaced, due to numerical rounding.
This occurs with some images created by earlier versions of spatstat.
To repair the coordinates in an image X, type
X <- as.im(X).xlim, ylim
such that xlim[1] > xlim[2] or ylim[1] > ylim[2] or
both. This bug is reported to occur only when useRaster=TRUE.
To fix this, try setting workaround=TRUE, or if that is
unsuccessful, useRaster=FALSE.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.
The legend consists of a colour ribbon and an axis with tick-marks,
showing the correspondence between the pixel values and the colour map.
By default, the ribbon is placed at the right of the main image.
This can be changed using the argument ribside.
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.
Arguments ribscale, ribargs control the annotation of the
colour ribbon. To plot the colour ribbon without the axis and
tick-marks, use ribargs=list(axes=FALSE).
Normally the pixel values are displayed using the colours given in the
argument col. This may be either
"colourmap", created by the command colourmap).
This is the best way to ensure
that when we plot different images, the colour maps are consistent.
x. The mapping of pixel values
to colours is determined as follows.
function in the R language
with an argument named range
or inputs.
If col is a function with an argument named range,
and if the pixel values of x are numeric values,
then the colour values will be determined by evaluating
col(range=range(x)). The result of this evaluation
should be a character vector containing colour values, or
a "colourmap" object. Examples of such functions
are beachcolours and beachcolourmap.
If col is a function with an argument named inputs,
and if the pixel values of x are discrete values (integer,
logical, factor or character),
then the colour values will be determined by evaluating
col(inputs=p) where p is the set of possible pixel
values. The result should be a character vector
containing colour values, or a "colourmap" object.
function in the R language with first argument
named n.
The colour values will be determined by evaluating
col(n) where n is the
number of distinct pixel values, up to a maximum of 128.
The result of this evaluation
should be a character vector containing color values.
Examples of such functions are
heat.colors,
terrain.colors,
topo.colors and
cm.colors.
If spatstat.options("monochrome") has been set to TRUE
then all colours will be converted to grey scale values.
Other graphical parameters controlling the display of both the pixel image
and the ribbon can be passed through the ... arguments
to the function image.default.
A parameter is handled only if it is one of the following:
image.default
that is operative when add=TRUE.
"main", "asp", "sub", "axes", "ann",
"cex", "font", "cex.axis", "cex.lab", "cex.main", "cex.sub",
"col.axis", "col.lab", "col.main", "col.sub",
"font.axis", "font.lab", "font.main", "font.sub"
described in par.
box, a logical value specifying whether
a box should be drawn.
Images are plotted using a bitmap raster if useRaster=TRUE
or by drawing polygons if useRaster=FALSE.
Bitmap raster display (performed by rasterImage)
tends to produce better results, but is not supported on all graphics devices.
The default is to use bitmap raster display if it is
supported according to dev.capabilities.
Alternatively, the pixel values could be directly interpretable as colour values in R. That is, the pixel values could be character strings that represent colours, or values of a factor whose levels are character strings representing colours.
valuesAreColours=TRUE, then the pixel values will
be interpreted as colour values and displayed using these colours.
valuesAreColours=FALSE, then the pixel values will
not be interpreted as colour values, even if they could be.
valuesAreColours=NULL, the algorithm will guess
what it should do. If the argument col is given,
the pixel values will not be interpreted as colour values. Otherwise,
if all the pixel values are strings that represent colours, then
they will be interpreted and displayed as colours.
If pixel values are interpreted as colours,
the arguments col and ribbon will be ignored,
and a ribbon will not be plotted.
im.object,
colourmap,
contour.im,
persp.im,
hist.im,
image.default,
spatstat.options
# an image
Z <- setcov(owin())
plot(Z)
plot(Z, ribside="bottom")
# stretchable colour map
plot(Z, col=terrain.colors(128), axes=FALSE)
# fixed colour map
tc <- colourmap(rainbow(128), breaks=seq(-1,2,length=129))
plot(Z, col=tc)
# colour map function, with argument 'range'
plot(Z, col=beachcolours, colargs=list(sealevel=0.5))
# tweaking the plot
plot(Z, main="La vie en bleu", col.main="blue", cex.main=1.5,
box=FALSE,
ribargs=list(col.axis="blue", col.ticks="blue", cex.axis=0.75))
# log scale
V <- eval.im(exp(exp(Z+2))/1e4)
plot(V, log=TRUE, main="Log scale")
# it's complex
Y <- exp(Z + V * 1i)
plot(Y)
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