ilagplot {IDPmisc}

Image Lag Plot Matrix for Large Time Series

Description

Produces an image lag plot matrix of large timeseries where the colors encode the density of the points in the lag plots.

Usage

ilagplot(x, set.lags = 1,
         pixs = 1, zmax = NULL, ztransf = function(x){x},
         colramp = IDPcolorRamp, mfrow=NULL, cex=par("cex"),
         main = NULL, d.main = 1, cex.main = 1.5*par("cex.main"),
         legend = TRUE, d.legend = 1,
         cex.axis = par("cex.axis"), las = 1,
         border=FALSE, mar = c(2,2,2,0), oma = rep(0,4)+0.1,
         mgp = c(2,0.5,0)*cex.axis, tcl = -0.3, ...)

Arguments

x

ts object or ordinary vector

set.lags

vector of lags to be displayed

pixs

Pixel size in mm

zmax

Maximum counts per Pixel to be plotted. When NULL each lag plot has its individual scale. If a number >= maximum number of counts per pixel is supplied, the scale will be identical for all lag plots. The maximum of the number per pixel is delivered by the return value. Beware: zmax has its meaning only for ilagplots with identical settings for main, legend, mar and oma!

ztransf

Function to transform the counts. The user has to make sure that the transformed counts lie in the range [0,zmax], where zmax is any positive number (>=2).

colramp

Color ramp to encode the density of the points within a pixel

mfrow

See Argument mfrow in par

cex

See Argument cex in par

main

Title

d.main

Vertical distance between upper border of scatter plots and the title line in multiples of title height.

cex.main

Magnification used for title relative to the current setting of cex.

legend

Logical. When FALSE, no legend is plotted and space is saved in figure region.

d.legend

Horizontal distance between right border of scatter plots and legend in multiples of title height.

cex.axis

Magnification used for axis annotation relative to the current setting of cex.

las

Orientation of labels on axes.

border

Logical. When TRUE, a border is drawn around the individual colors in the legend.

mar, oma

Margin and outer margin respectively. Cf. par

mgp, tcl

Cf. par

...

Additional arguments to par

Details

Code is based on R function lag.plot V1.7. Tip: Legend looks better when mar is defined symmetrically.

Value

Maximum number of counts per Pixel found.

Note

When you get the error message "Zmax too small! Densiest aereas are out of range!" you must run the function with identical parameters but without specifying zmax. The value returned gives you the minimum value allowed for zmax.

Author(s)

Andreas Ruckstuhl, refined by Rene Locher

See Also

ipairs, iplot, Image

Examples

if(require(SwissAir)) {
  data(AirQual)

  ilagplot(AirQual[,c("ad.O3")],set.lags = 1:4,
           ztransf = function(x){x[x<1] <- 1; log2(x)},
           main = "Low correlation")

  Ox <- AirQual[,c("ad.O3","lu.O3","sz.O3")]+
    AirQual[,c("ad.NOx","lu.NOx","sz.NOx")]-
      AirQual[,c("ad.NO","lu.NO","sz.NO")]
  names(Ox) <- c("ad","lu","sz")
  ilagplot(Ox$ad,set.lags = 1:4,
           ztransf = function(x){x[x<1] <- 1; log2(x)},
           main = "High correlation")

  ## cf. ?AirQual for the explanation of the physical
  ## and chemical background
} else print("Package SwissAir is not available")