Matrixplot

Plots a color matrix, representing the values stored in x.
Originally, it was thought to represent the amount of days with information per year in a set of gauging stations, but it can be used for plotting the information stored in any two dimensional matrix.

Usage

matrixplot(x, ColorRamp="Days", ncolors = 10, main = "", 
           cuts,  cuts.dec=2, cuts.labels, 
           cuts.style=c("equal", "pretty", "fixed", "sd", "quantile", 
                        "kmeans", "bclust", "fisher"), 
           legend.cex=0.8,  legend.title="",  legend.title.cex=1.5, 
           legend.fontsize=15, ...)

Arguments

x: matrix to be plotted. Originally:
-) Each column of x represent a different gauging station, and it stores the values measured on it
-) Each row of x represent the years, and they stores the amount of days with information in each station
ColorRamp: Character or function defining a personalized color ramp for plotting the maps.
Valid character values are in c("Days", "Precipitation", "Temperature", "PCPAnomaly", "PCPAnomaly2" "TEMPAnomaly", "TEMPAnomaly2", "TEMPAnomaly3").
ncolors: numeric, indicating the number of color intervals that will be used for representing the information content of x.
main: Main title for the plot
cuts: Numeric, indicating the values used to divide the range of 'x' in the legend of colours. If not provided, it is automatically selected as a function of 'lenght(ColorRamp)'.
cuts.dec: Number of decimal places used to present the numbers that divide the range of 'x' in the legend of colours.
cuts.labels: Character indicating the label to be used in the ccolour legend for each one of the values defined by 'cuts'. If not provided, as.character(cuts)' is used.
cuts.style: character, indicating how to finding class intervals for continuous numerical variables for choosing colours to be used in the figure. See classIntervals
legend.cex: character expansion factor *relative* to current par("cex") used for the legend text.
legend.title: text to be displayed above the legned of colours (e.g., showing the measurement units of the raster being displayed).
legend.title.cex: expansion factor(s) for the legend title. Currently it is not used. See legend.fontsize instead.
legend.fontsize: size of text (in points) used in the legend title (e.g., showing the measurement units of the raster being displayed).
...: further arguments passed to levelplot function (lattice package) or from other methods

Details

The default levelplot panel draws dotted grey lines along cell boundaries, making individual matrix values easier to distinguish.

Author

Mauricio Zambrano-Bigiarini, mzb.devel@gmail

Note

Adapted from a not available web page (http://www2.warwick.ac.uk/fac/sci/moac/currentstudents/peter_cock/r/matrix_contour/)

Examples

## Loading the SanMartino precipitation data
data(SanMartinoPPts)

# Selecting only the values up to Dec/1960
x <- window(SanMartinoPPts, end=as.Date("1960-12-31"))

## Daily zoo to monthly zoo
m <- daily2monthly(x, FUN=sum, na.rm=TRUE)

# Creating a data.frame with monthly values per year in each column
M <- matrix(m, ncol=12, byrow=TRUE)
colnames(M) <- month.abb
rownames(M) <- unique(format(time(m), "%Y"))

# Plotting the monthly precipitation values from 1921 to 1960.
# Useful for identifying dry/wet months
matrixplot(M, ColorRamp="Precipitation", 
           main="Monthly precipitation at San Martino st., [mm/month]")