oce (version 0.1-76)

plot.section: Plot a CTD section

Description

Plot a CTD section.

Usage

## S3 method for class 'section':
plot(x,
 	field=NULL,
	at=NULL,
	labels=TRUE,
	grid=FALSE,
        contour.levels=NULL,
        contour.labels=NULL,
	station.indices,
	coastline=NULL,
	map.xlim=NULL,
        xtype="distance",
        ytype="depth",
        legend.loc="bottomright",
	\dots)

Arguments

x

a section object, e.g. as created by make.section.

field

is the field to plot. Common options are "temperature", "salinity", and "density", although plot.section will accept any named field that is present in the constituent CTD profiles. If

at

if NULL (the default), the x axis will indicate the distance of the stations from the first in the section. (This may give errors in the contouring routine, if the stations are not present in a geographical order.) If a list, th

labels

either a logical, indicating whether to put labels on the x axis, or a vector that is a list of labels to be placed at the x positions indicated by at.

grid

if TRUE, points are drawn at data locations.

contour.levels

if not NULL, and if a field was specified, this specifies contour levels (see details)

contour.labels

if not NULL, and if a field was specified, this specifies contour labels (see details)

station.indices

optional list of the indices of stations to use. Note that these are indices, not the names of stations, e.g. to focus on the first four stations, use station.numbers=c(1,4).

coastline

optional coastline to be used in a station map

map.xlim

optional xlim for station location, which can be helpful in ensuring that a recognizable coastline can be seen

xtype

type of x axis, for contour plots, either "distance" for distance (in km) to the first point in the section, or "track" for distance along the cruise track. Note that if the x values are not in order, they will be put

ytype

type of y axis for contour plots, either "pressure" for pressure (in dbar, with zero at the surface) or "depth" for depth (in m below the surface, calculated from pressure with s

legend.loc

location of legend, as supplied to legend.

...

optional arguments passed to the contouring function, e.g. using labcex=1 will increase the size of contour labels.

Value

• None.

Details

Creates a summary plot for a CTD section. If a field is supplied, then just that single field is contoured. If no field is supplied, then temperature, salinity, and sigma are contoured. A location plot is also drawn if a coastline is provided; in this, the first station in the section is indicated with a different symbol than the rest.

The y-axis for the contours is pressure, plotted in the conventional reversed form, so that the water surface appears at the top of the plot. The x-axis is more complicated. If at is not supplied, then the routine calculates x as the distance between the first station in the section and each of the other stations. (This will produce an error if the stations are not ordered geographically, because the contour routine cannot handle non-increasing axis coordinates.) If at is specified, then it is taken to be the location, in arbitrary units, along the x-axis of labels specified by labels; the way this works is designed to be the same as for axis.

See Also

Sections may be created with make.section or read.section, and may be summarized with summary.section.

Examples

library(oce)
# Halifax Harbour
data(section)
data(coastline.hal)
plot(section, coastline=coastline.hal)
# Gulf Stream
data(a03)
Gulf.Stream <- subset(a03, indices=124:102)
Gulf.Stream.gridded <- section.grid(Gulf.Stream, p=seq(0,2000,100))
data(coastline.world)
plot(Gulf.Stream.gridded, coastline=coastline.world, map.xlim=c(-80,-60))