ipairs {IDPmisc} | R Documentation |
Produces an image scatter plot matrix of large datasets where the colors encode the density of the points in the scatter plots.
ipairs(x, pixs = 1, zmax = NULL, ztransf=function(x){x}, colramp = IDPcolorRamp, lab.diag, cex.diag = NULL, main = NULL, d.main = 1, cex.main = 2*par("cex.main"), legend = TRUE, d.legend = 1, cex.axis = par("cex.axis"), nlab.axis = 5, minL.axis = 2, las = 1, border = FALSE, mar = rep(0,4), oma = c(3,3,1,0), ...)
x |
data.frame or matrix |
pixs |
Pixel size in mm on the plotting device. |
zmax |
Maximum number of counts per pixel in the plot. When NULL, each scatter plot has its individual scale. If a number >= maximum number of counts per pixel is supplied, the scale will be identical for all scatter plots. The maximum number of counts per pixel is delivered by the return value. |
ztransf |
Function to transform the counts per
pixel, which will be mapped by the function in
colramp to well defined colors. 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 number of counts within a pixel. |
lab.diag |
Labels of columns, written into the diagonal of the
matrix. When NULL , the names of x are used. |
cex.diag |
Magnification used for text in diagonal relative to
the current setting of cex.
When NULL , they are calculated automatically. |
main |
Titel. When NULL |
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. |
nlab.axis |
Approximate number of labels on axes. |
minL.axis |
The minimum length of the abbreviations of factor levels, used to label the axes ticks. |
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 |
... |
Additional arguments to par |
The idea is similar to gplot.hexbin
. The
hexagons are better suited to reflect the density of points in a plane
than the squares used here. Nevertheless squares are, contrary to
hexagons, invariant to reflexions at the x- and y-axis and
therefore better suited for scatter plot matrices and also for
plotting factors.
The code is based on R function pairs
V1.7.
Maximum number of counts per Pixel found. Additional elements are
returned when verbose == TRUE
.
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.
Andreas Ruckstuhl, Rene Locher
## Small numbers of different values are plotted nicer ## when converted to factors AQ <- airquality AQ$Month <- as.factor(AQ$Month) zmax <- ipairs(AQ, pixs=2, main="Air Quality") ipairs(AQ, pixs=2, zmax=zmax, main="Air Quality",border=TRUE) ## example with factors ipairs(iris,pixs=2) ## a really huge dataset if(require(SwissAir)) { data(AirQual) ## low correlation ipairs(AirQual[,c("ad.O3","lu.O3","sz.O3")], ztransf=function(x){x[x<1] <- 1; log2(x)}) ipairs(AirQual[,c("ad.NO","lu.NO","sz.NO")], ztransf=function(x){x[x<1] <- 1; log2(x)}) ## 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") ipairs(Ox, ztransf=function(x){x[x<1] <- 1; log2(x)}) ## cf. ?AirQual for the explanation of the physical and ## chemical background } else print("Package SwissAir is not available")