R: Create a Section

as.section {oce} | R Documentation

## Create a Section

### Description

Create a section based on columnar data, or a set of `oce-class` objects that can be coerced to a section. There are three cases.

Case 1. If the first argument is a numerical vector, then it is taken to be the salinity, and `factor` is applied to `station` to break the data up into chunks that are assembled into `ctd-class` objects with `as.ctd` and combined to make a `section-class` object to be returned. This mode of operation is provided as a convenience for datasets that are already partly processed; if original CTD data are available, the next mode is preferred, because it permits the storage of much more data and metadata in the CTD object.

Case 2. If the first argument is a list containing oce objects, then those objects are taken as profiles of something. A requirement for this to work is that every element of the list contains both `longitude` and `latitude` in either the `metadata` or `data` slot (in the latter case, the mean value is recorded in the section object) and that every element also contains `pressure` in its `data` slot.

Case 3. If the first argument is a `argo-class` object, then the profiles it contains are turned into `ctd-class` objects, and these are assembled into a section to be returned.

### Usage

    as.section(salinity, temperature, pressure, longitude, latitude, station,
      sectionId = "")

### Arguments

`salinity` | This may be a numerical vector, in which case it is interpreted as the salinity, and the other arguments are used for the other components of `ctd-class` objects. Alternatively, it may be one of a variety of other objects from which the CTD objects can be inferred, in which case the other arguments are ignored; see ‘Details’.
`temperature` | Temperature, in a vector holding values for all stations.
`pressure` | Pressure, in a vector holding values for all stations.
`longitude` | Longitude, in a vector holding values for all stations.
`latitude` | Latitude, in a vector holding values for all stations.
`station` | Station identifiers, in a vector holding values for all stations.
`sectionId` | Section identifier.

### Value

An object of `section-class`.

### Author(s)

Dan Kelley

### See Also

Other things related to section data: `[[,section-method`, `[[<-,section-method`, `handleFlags,section-method`, `initializeFlagScheme,section-method`, `plot,section-method`, `read.section`, `section-class`, `sectionAddStation`, `sectionGrid`, `sectionSmooth`, `sectionSort`, `section`, `subset,section-method`, `summary,section-method`

### Examples

    library(oce)
    data(ctd)
    ## vector of names of CTD objects
    fake <- ctd
    fake[["temperature"]] <- ctd[["temperature"]] + 0.5
    fake[["salinity"]] <- ctd[["salinity"]] + 0.1
    fake[["longitude"]] <- ctd[["longitude"]] + 0.01
    fake[["station"]] <- "fake"
    sec1 <- as.section(c("ctd", "fake"))
    summary(sec1)
    ## vector of CTD objects
    ctds <- vector("list", 2)
    ctds[[1]] <- ctd
    ctds[[2]] <- fake
    sec2 <- as.section(ctds)
    summary(sec2)
    ## argo data (a subset)
    data(argo)
    sec3 <- as.section(subset(argo, profile<5))
    summary(sec3)

[Package oce version 1.1-1 Index]