ilagplot {IDPmisc}R Documentation

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, border = FALSE,
         main = NULL, cex.main = 2 * par("cex.main"), ...)

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 vallue.
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
border Shall border be drawn between the colors in the legend: TRUE / FALSE
main Title
cex.main Character size of title
... Additional arguments to plot.default

Details

Code is based on R function lag.plot V1.7.

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 again 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, ixyplot, Image

Examples

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

  ## low correlation
  ilagplot(AirQual[,c("ad.O3")],set.lags = 1:9,
         ztransf=function(x){x[x<1] <- 1; log2(x)*10})

  ## high 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 = 1:9,
           ztransf=function(x){x[x<1] <- 1; log2(x)*10})

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

[Package IDPmisc version 0.9.1 Index]