heat_ppoints
plots a "heated" scatterplot for
(potentially) projected locations. A color scale is
automatically provided with the scatterplot. The function
is similar in purpose to pimage
,
but the z
-values are not interpolated. The color
scale can be changed by passing a vector of colors to
the col
argument.
heat_ppoints(
x,
y,
z,
legend = "horizontal",
proj = "none",
parameters,
orientation,
lratio = 0.2,
map = "none",
n = 5,
...
)
Numeric vectors of coordinates at which the
values in z
are measured.
A numeric vector containing the values to be plotted.
A character string indicating where the
color scale should be placed. The default is
"horizontal"
. The other valid options are
"none"
and "vertical"
.
A character string indicating what projection
should be used for the included x
and y
coordinates. The default is "none"
. The other
valid choices correspond to the "projection"
argument in the mapproject
function, which is used for the projection.
A numeric vector specifying the values
of the parameters
argument in the
mapproject
. This may be
necessary when proj != "none"
.
A vector
c(latitude,longitude,rotation)
which describes
where the "North Pole" should be when computing the
projection. See mapproject
for
more details.
A numeric value indicating the ratio of the
smaller dimension of the legend scale to the width of
the image. Default is lratio = 0.2
.
The name of the map to draw on the image.
Default is "none"
. Other options include
"world"
, "usa"
, "state"
,
"county"
, "france"
, "nz"
(New
Zealand), "italy"
, "lakes"
, and
"world2"
, all from the maps
package.
integer giving the desired number of intervals. Non-integer values are rounded down.
Additional arguments passed to the
plot
function. e.g.,
xlab
, ylab
, xlim
, ylim
,
zlim
, etc. Additionally, arguments that can be
used to further customize the plot (like adding lines
or points), as described in Details and Examples.
When proj != "none"
, the
mapproject
function is used to
project the x
and y
coordinates. In that
case, proj
must correspond to one of the choices
for the projection
argument in the
mapproject
function. Necessary
arguments for mapproject
should be
provided via the parameters
and orientation
arguments. See Examples and the
mapproject
function.
Valid options for legend
are "none"
,
"horizontal"
, and "vertical"
. If
legend = "none"
, then no color scale is provided.
If legend = "horizontal"
, then a color scale is
included under the plot. If legend = "vertical"
,
then a color scale is added to the right of the plot.
Lines can be added to each plot by passing the
lines
argument through ...
. In that case,
lines
should be a list with components x
and y
specifying the locations to draw the lines.
The appearance of the plotted lines can be customized by
passing a named list called lines.args
through
...
. The components of lines.args
should
match the arguments of lines
.
See Examples.
Points can be added to each image by passing the
points
argument through ...
. In that case,
points
should be a list with components x
and y
specifying the locations to draw the points.
The appearance of the plotted points can be customized by
passing a named list called points.args
through
...
. The components of points.args
should
match the components of points
.
See Examples.
Text can be added to each image by passing the
text
argument through ...
. In that case,
text
should be a list with components x
and
y
specifying the locations to draw the text, and
labels
, a component specifying the actual text to
write. The appearance of the plotted text can be
customized by passing a named list called
text.args
through ...
. The components of
text.args
should match the components of
text
. See Examples.
The legend scale can be modified by passing
legend.axis.args
through ...
. The argument
should be a named list corresponding to the arguments of
the axis
function. See Examples.
The plot axes can be modified by passing
axis.args
through ...
. The argument should
be a named list corresponding to the arguments of the
axis
function. The exception to
this is that arguments xat
and yat
can be
specified (instead of at
) to specify the location
of the x and y ticks. If xat
or yat
are
specified, then this overrides the xaxt
and
yaxt
arguments, respectively. See the
paxes
function to see how
axis.args
can be used.
The legend margin can be customized by passing
legend.mar
to heat_ppoints
through ...
.
This should be a numeric vector indicating the margins of
the legend, identical to how par("mar")
is
specified.
The various options of the labeling, axes, and legend are
largely independent. e.g., passing col.axis
through ...
will not affect the axis unless it is
passed as part of the named list axis.args
.
However, one can set the various par
options prior
to plotting to simultaneously affect the appearance of
multiple aspects of the plot. See Examples. After
plotting, reset.par()
can be used to reset the
graphics device options to their default values.
# NOT RUN {
data(co, package = "gear")
# heated scatterplot for data on an irregular grid
heat_ppoints(co$lon, co$lat, co$Al, legend = "v", map = "state")
reset.par()
# change color scale
heat_ppoints(co$lon, co$lat, co$Al, col = cm.colors(5))
reset.par()
# Use custom border, x and y limits, breaks for legend axis
data(copoly)
heat_ppoints(co$lon, co$lat, co$Al, legend = "h",
xlab = "longitude", ylab = "latitude",
proj = "bonne", parameters = 40,
lines = copoly,
lines.args = list(lwd = 2, col = "grey"),
xlim = c(-109.1, -102),
ylim = c(36.8, 41.1),
breaks = seq(0, 10, len = 6))
reset.par()
# }
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