plotAdjustedRtime: Visualization of alignment results

Description Usage Arguments Author(s) See Also Examples

View source: R/functions-XCMSnExp.R

Description

Plot the difference between the adjusted and the raw retention time (y-axis) for each file along the (adjusted or raw) retention time (x-axis). If alignment was performed using the adjustRtime-peakGroups method, also the features (peak groups) used for the alignment are shown.

Usage

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plotAdjustedRtime(
  object,
  col = "#00000080",
  lty = 1,
  lwd = 1,
  type = "l",
  adjustedRtime = TRUE,
  xlab = ifelse(adjustedRtime, yes = expression(rt[adj]), no = expression(rt[raw])),
  ylab = expression(rt[adj] - rt[raw]),
  peakGroupsCol = "#00000060",
  peakGroupsPch = 16,
  peakGroupsLty = 3,
  ylim,
  ...
)

Arguments

object

A XCMSnExp object with the alignment results.

col

colors to be used for the lines corresponding to the individual samples.

lty

line type to be used for the lines of the individual samples.

lwd

line width to be used for the lines of the individual samples.

type

plot type to be used. See help on the par function for supported values.

adjustedRtime

logical(1) whether adjusted or raw retention times should be shown on the x-axis.

xlab

the label for the x-axis.

ylab

the label for the y-axis.

peakGroupsCol

color to be used for the peak groups (only used if alignment was performed using the adjustRtime-peakGroups method.

peakGroupsPch

point character (pch) to be used for the peak groups (only used if alignment was performed using the adjustRtime-peakGroups method.

peakGroupsLty

line type (lty) to be used to connect points for each peak groups (only used if alignment was performed using the adjustRtime-peakGroups method.

ylim

optional numeric(2) with the upper and lower limits on the y-axis.

...

Additional arguments to be passed down to the plot function.

Author(s)

Johannes Rainer

See Also

adjustRtime for all retention time correction/ alignment methods.

Examples

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## Below we perform first a peak detection (using the matchedFilter
## method) on some of the test files from the faahKO package followed by
## a peak grouping and retention time adjustment using the "peak groups"
## method
library(faahKO)
library(xcms)
fls <- dir(system.file("cdf/KO", package = "faahKO"), recursive = TRUE,
           full.names = TRUE)

## Reading 2 of the KO samples
raw_data <- readMSData(fls[1:2], mode = "onDisk")

## Perform the peak detection using the matchedFilter method.
mfp <- MatchedFilterParam(snthresh = 20, binSize = 1)
res <- findChromPeaks(raw_data, param = mfp)

## Performing the peak grouping using the "peak density" method.
p <- PeakDensityParam(sampleGroups = c(1, 1))
res <- groupChromPeaks(res, param = p)

## Perform the retention time adjustment using peak groups found in both
## files.
fgp <- PeakGroupsParam(minFraction = 1)
res <- adjustRtime(res, param = fgp)

## Visualize the impact of the alignment. We show both versions of the plot,
## with the raw retention times on the x-axis (top) and with the adjusted
## retention times (bottom).
par(mfrow = c(2, 1))
plotAdjustedRtime(res, adjusted = FALSE)
grid()
plotAdjustedRtime(res)
grid()

yclement/xcms documentation built on April 10, 2020, 12:08 a.m.