rgr: ad.plot2 – R documentation

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ad.plot2

Plot Results of Analytical Duplicate Analyses, Alternate Input

Description

Function to prepare data stored in alternate forms from that expected by function ad.plot1 for its use, for further details see x in Arguments below. The data will be plotted as the percent absolute difference between duplicates relative to their accession order or their means.

Usage

ad.plot2(x, xname = deparse(substitute(x)), if.order = TRUE, 
	if.rsds = FALSE, ldl = NULL, ad.tol = NULL, log = FALSE,
	ifalt = FALSE, ...)

Arguments

`x`	a column vector from a matrix or data frame, `x[1], ..., x[2*n]`. The default is that the first n members of the vector are the first measurements and the second n members are the duplicate measurements. If the measurements alternate, i.e. duplicate pair 1 measurement 1 followed by measurement 2, etc., set `ifalt = TRUE`.
`xname`	a title can be displayed with the plot and results, e.g., `xname = "Cu (mg/kg)"`. If this field is undefined the character string for `x` is used as a default.
`if.order`	by default the analytical duplicate results are plotted in the order in which they occur in the data file, this usually corresponds to date of analysis in a time-series. Alternately, setting `if.order = FALSE` results in the individual duplicate results being plotted against their means.
`if.rsds`	by default the absolute difference between the duplicates expressed as a percentage of their mean is plotted on the y-axis. If it is required to plot the relative standard deviations (RSDs), set `if.rsds = TRUE`.
`ldl`	by default the x-axis is defined by the measurement units. If it is desired to express the duplicate means as a ratio to the lower detection limit (ldl) of the analytical procedure, then set `ldl = 'ldl'` in measurement units.
`ad.tol`	optionally a tolerance level may be provided for the maximum acceptable percent absolute relative difference between duplicates, in which case a red dotted line is added to the plot.
`log`	optionally the x-axis of the plot employing duplicate means may be plotted with logarithmic scaling, if so, set `log = TRUE`.
`ifalt`	set `ifalt = TRUE` to accommodate alternating sets of paired observations.
`...`	any additional arguments to be passed to the `plot` function for titling, etc.

Details

Data may be as a single concatenated vector from a matrix or data frame as x1[1], ..., x1[n] followed by x[n+1], ..., x[2n], or alternated as x[1] and x[2] being a pair through to x[2*i+1] and x[2*i+2] for the i in 1:n duplicate pairs, see ifalt.

If the data are as n duplicate pairs, x1 and x2, use function ad.plot1.

Note

Any less than detection limit values represented by negative values, or zeros or other numeric codes representing blanks in the data, must be removed prior to executing this function, see ltdl.fix.df.

Author(s)

Robert G. Garrett

Examples

## Make test data available
data(ad.test)
attach(ad.test)

## Plot analytical duplicate analyses as a time-series
ad.plot2(Cu, ifalt = TRUE)

## Plot analytical duplicate analyses versus duplicate means,
## annotating more appropriately, with a 20% maximum tolerance
ad.plot2(Cu, "Cu (mg/kg)", if.order = FALSE, ad.tol = 20, ifalt = TRUE)

## Detach test data
detach(ad.test)

rgr

Applied Geochemistry EDA

v1.1.15

GPL-2

Authors

Robert G. Garrett

Initial release

2018-03-05