sectionGrid: Grid a section

Description

Grid a section, by interpolating to fixed pressure levels.

Usage

sectionGrid(section, p, method=c("approx","boxcar","lm"), 
             debug=getOption("oceDebug"), ...)

Arguments

section

a section object containing the section to be gridded.

optional indication of the pressure levels to which interpolation should be done. If this is not supplied, the pressure levels will be calculated based on the typical spacing in the ctd profiles stored within section. If a single numerical

method

the algorithm to use for interpolation to the pressure levels; see Details below for a sketch, and see ctdDecimate for a deeper discussion.

debug

a flag that turns on debugging. The value indicates the depth within the call stack to which debugging applies. For example, read.adv.nortek() calls read.header.nortek(), so that read.adv.nortek(...,debug=2)

...

optional arguments to be supplied to
    ctdDecimate.

`Value`

An object of class "section" that
  contains stations whose pressure values match identically.

`Details`

The "approx", "boxcar" and "lm" methods are described in the documentation for ctdDecimate, which is used to do this processing.  The default "approx" method is best for bottle data, the "boxcar" is best for ctd data, and the "lm" method is probably too slow to recommend for exploratory work, in which it is common to do trials with a variety of "p" values.

`See Also`

Sections are normally created with read.section
  or makeSection.  subset may be used to
  create a new section consisting of just a subset of an existing
  station, e.g. to focus on a particular region.

`Examples`

Run this code# Gulf Stream
library(oce)
# File source -- http://cchdo.ucsd.edu/data_access?ExpoCode=90CT40_1
# a03 <- read.section("a03_hy1.csv")
data(a03)
GS <- subset(a03, indices=124:102)
GSg <- sectionGrid(GS, p=seq(0, 5000, 100))
data(coastlineWorld)
plot(GSg, coastline=coastlineWorld, map.xlim=c(-80,-60))
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