concareaExampleKola function

Concentration Area Plot for Kola data example

Displays a concentration area plot example for the Kola data. This procedure ist useful for determining if mulitple populations that are spatially dependent are present in a data set. For a more general function see concarea.

concareaExampleKola(x, y, z, zname = deparse(substitute(z)),
caname = deparse(substitute(z)), borders="bordersKola", logx = FALSE, ifjit = FALSE,
ifrev = FALSE, ngrid = 100, ncp = 0, xlim = NULL, xcoord = "Easting",
ycoord = "Northing", ifbw = FALSE, x.logfinetick = c(2, 5, 10),
y.logfinetick = c(2, 5, 10))

Arguments

• x: name of the x-axis spatial coordinate, the eastings
• y: name of the y-axis spatial coordinate, the northings
• z: name of the variable to be processed and plotted
• zname: a title for the x-axes of the qp-plot and concentration area plot.
• caname: a title for the image of interpolated data.
• borders: either NULL or character string with the name of the list with list elements x and y for x- and y-coordinates of map borders
• logx: if it is required to make a logarithmis data transformation for the interpolation
• ifrev: if FALSE the empirical function ist plotted from highest value to lowest
• ngrid: default value is 100
• xlim: the range for the x-axis
• xcoord: a title for the x-axis, defaults to "Easting"
• ycoord: a title for the y-axis, defaults to "Northing"
• ifbw: if the plot is drawn in black and white
• x.logfinetick: how fine are the tick marks on log-scale on x-axis
• y.logfinetick: how fine are the tick marks on log-scale on y-axis
• ifjit: default value is FALSE
• ncp: default value is 0

Details

The function assumes that the area is proportional to the count of grid points. To be a reasonable model the data points should be 'evenly' spread over the plane. The interpolated grid size ist computed as (max(x) - min(x))/ngrid, with a default value of 100 for ngrid. Akima's interpolation function is used to obtain a linear interpolation between the spatial data values.

Returns

An example concentration area plot for Kola is created.

References

C. Reimann, P. Filzmoser, R.G. Garrett, and R. Dutter: Statistical Data Analysis Explained. Applied Environmental Statistics with R. John Wiley and Sons, Chichester, 2008.

Author(s)

Peter Filzmoser <P.Filzmoser@tuwien.ac.at > http://cstat.tuwien.ac.at/filz/

See Also

qpplot.das, concarea

Examples

data(ohorizon)
data(kola.background)
data(bordersKola)

Cu=ohorizon[,"Cu"]
X=ohorizon[,"XCOO"]
Y=ohorizon[,"YCOO"]

op <- par(mfrow=c(2,2),mar=c(1.5,1.5,1.5,1.5))
concareaExampleKola(X,Y,Cu,log=TRUE,zname="Cu in O-horizon [mg/kg]",
   x.logfinetick=c(2,5,10),y.logfinetick=c(10))
par(op)