spoints: Scatter plot with a color scale

In npsp: Nonparametric Spatial Statistics

Scatter plot with a color scale

Description

spoints (generic function) draws a scatter plot with points filled with different colors and (optionally) adds a legend strip with the color scale (calls splot and plot.default).

Usage

spoints(x, ...)

## Default S3 method:
spoints(
  x,
  y = NULL,
  s,
  slim = range(s, finite = TRUE),
  col = jet.colors(128),
  breaks = NULL,
  legend = TRUE,
  horizontal = FALSE,
  legend.shrink = 1,
  legend.width = 1.2,
  legend.mar = ifelse(horizontal, 3.1, 5.1),
  legend.lab = NULL,
  bigplot = NULL,
  smallplot = NULL,
  lab.breaks = NULL,
  axis.args = NULL,
  legend.args = NULL,
  add = FALSE,
  reset = TRUE,
  pch = 16,
  cex = 1.5,
  xlab = NULL,
  ylab = NULL,
  asp = NA,
  ...
)

## S3 method for class 'data.grid'
spoints(x, s = x[[1]], xlab = NULL, ylab = NULL, ...)

## S3 method for class 'SpatialPointsDataFrame'
spoints(x, data.ind = 1, main, xlab, ylab, legend.lab, ...)

Arguments

x	object used to select a method. In the default method, it provides the x coordinates for the plot (and optionally the y coordinates; any reasonable way of defining the coordinates is acceptable, see the function xy.coords for details).
...	additional graphical parameters (to be passed to the main plot function or sxxxx.default; e.g. xlim, ylim, ...). NOTE: graphical arguments passed here will only have impact on the main plot. To change the graphical defaults for the legend use the par function beforehand (e.g. par(cex.lab = 2) to increase colorbar labels).
y	y coordinates. Alternatively, a single argument x can be provided.
s	numerical vector containing the values used for coloring the points.
slim	limits used to set up the color scale.
col	color table used to set up the color scale (see image for details).
breaks	(optional) numeric vector with the breakpoints for the color scale: must have one more breakpoint than col and be in increasing order.
legend	logical; if TRUE (default), the plotting region is splitted into two parts, drawing the main plot in one and the legend with the color scale in the other. If FALSE only the (coloured) main plot is drawn and the arguments related to the legend are ignored (splot is not called).
horizontal	logical; if FALSE (default) legend will be a vertical strip on the right side. If TRUE the legend strip will be along the bottom.
legend.shrink	amount to shrink the size of legend relative to the full height or width of the plot.
legend.width	width in characters of the legend strip. Default is 1.2, a little bigger that the width of a character.
legend.mar	width in characters of legend margin that has the axis. Default is 5.1 for a vertical legend and 3.1 for a horizontal legend.
legend.lab	label for the axis of the color legend. Default is no label as this is usual evident from the plot title.
bigplot	plot coordinates for main plot. If not passed, and legend is TRUE, these will be determined within the function.
smallplot	plot coordinates for legend strip. If not passed, and legend is TRUE, these will be determined within the function.
lab.breaks	if breaks are supplied these are text string labels to put at each break value. This is intended to label axis on a transformed scale such as logs.
axis.args	additional arguments for the axis function used to create the legend axis (see image.plot for details).
legend.args	arguments for a complete specification of the legend label. This is in the form of list and is just passed to the mtext function. Usually this will not be needed (see image.plot for details).
add	logical; if TRUE the scatter plot is just added to the existing plot.
reset	logical; if FALSE the plotting region (par("plt")) will not be reset to make it possible to add more features to the plot (e.g. using functions such as points or lines). If TRUE (default) the plot parameters will be reset to the values before entering the function.
pch	vector of plotting characters or symbols: see points.
cex	numerical vector giving the amount by which plotting characters and symbols should be scaled relative to the default. This works as a multiple of par("cex").
xlab	label for the x axis, defaults to a description of x.
ylab	label for the y axis, defaults to a description of y.
asp	the y/x aspect ratio, see plot.window.
data.ind	integer (or character) with the index (or name) of the data component.
main	an overall title for the plot.

Details

spoints.SpatialPointsDataFrame sets default values for some of the arguments from attributes of the object x (if present; see e.g. precipitation).

Value

Invisibly returns a list with the following 3 components:

bigplot	plot coordinates of the main plot. These values may be useful for drawing a plot without the legend that is the same size as the plots with legends.
smallplot	plot coordinates of the secondary plot (legend strip).
old.par	previous graphical parameters (par(old.par) will reset plot parameters to the values before entering the function).

Side Effects

After exiting, the plotting region may be changed (par("plt")) to make it possible to add more features to the plot (set reset = FALSE to avoid this).

Author(s)

Based on image.plot function from package fields: fields, Tools for spatial data. Copyright 2004-2013, Institute for Mathematics Applied Geosciences. University Corporation for Atmospheric Research.

Modified by Ruben Fernandez-Casal <[e-mail]>.

See Also

splot, simage, spersp, image, image.plot, data.grid, plot.default.

Examples

with( aquifer, spoints(lon, lat, head, main = "Wolfcamp aquifer data"))

npsp documentation built on May 29, 2024, 5:31 a.m.