ptw (version 1.9-11)

gaschrom: 16 calibration GC traces

Description

The object gaschrom contains 16 calibration GC traces, measured at 5,000 time points. A peak-picked version is available as object gaschrom.st (see example).

Usage

data(gaschrom)

Source

Claire Boucon, Unilever

References

Eilers, P.H.C. (2004) "Parametric Time Warping", Analytical Chemistry, 76 (2), 404 -- 411.

Examples

data(gaschrom)

## the gaschrom.st object has been generated in the following way:
## Not run: 
# pick.peaks <- function(x, span) {
#   span.width <- span * 2 + 1
#   loc.max <- span.width + 1 -
#       apply(embed(x, span.width), 1, which.max)
#   loc.max[loc.max == 1 | loc.max == span.width] <- NA
#   
#   pks <- loc.max + 0:(length(loc.max)-1)
#   pks <- pks[!is.na(pks)]
#   pks.tab <- table(pks)
#   
#   pks.id <- as.numeric(names(pks.tab)[pks.tab > span])
#   
#   cbind(rt = pks.id, I = x[pks.id])
# }
# 
# gaschrom <- t(apply(gaschrom, 1, baseline.corr))
# gaschrom.st <- lapply(1:nrow(gaschrom), 
#                       function(ii) 
#                       pick.peaks(gaschrom[ii,], span = 11))
# ## remove peaks with an intensity below 10
# gaschrom.st <- lapply(gaschrom.st,
#                       function(pk)
#                       pk[pk[,2] >= 10,])
# ## End(Not run)
plot(gaschrom[1,], type = "l", xlim = c(3000, 3500), ylim = c(0, 200))
abline(h = 10, lty = 2, col = 2)
abline(v = gaschrom.st[[1]], col = 4)