oce (version 0.9-18)

plot.gps: Plot a gps object

Description

Plot a gps object

Usage

## S3 method for class 'gps':
plot(x,
     xlab="", ylab="",
     asp,
     clongitude, clatitude, span,
     projection, parameters=NULL, orientation=NULL,
     expand=1,
     mgp=getOption("oceMgp"), 
     mar=c(mgp[1]+1,mgp[1]+1,1,1),
     bg,
     axes=TRUE, cex.axis=par('cex.axis'),
     add=FALSE, inset=FALSE,
     geographical=0,
     debug=getOption("oceDebug"),
     ...)

Arguments

x

A gps object, as read by read.gps or created by as.gps, or a list containing items named longitude and latitude

xlab

label for x axis

ylab

label for y axis

asp

Aspect ratio for plot. The default is for plot.gps to set the aspect ratio to give natural latitude-longitude scaling somewhere near the centre latitude on the plot. Often, it makes sense to set asp yourself, e

clongitude,clatitude

optional center latitude of map, in decimal degrees. If both clongitude and clatitude are provided, then any provided value of asp is ignored, and instead the plot aspect ratio is computed based on

span

optional suggested span of plot, in kilometers. The suggestion is an upper limit on the scale; depending on the aspect ratio of the plotting device, the radius may be smaller than span. A value for span must b

projection

optional map projection to use (see mapPlot); if not given, a cartesian frame is used, scaled so that gps shapes near the centre of the plot are preserved. If a projection is provided, th

parameters

optional parameters to map projection (see mapPlot.

orientation

optional orientation of map projection (see mapPlot.

expand

numerical factor for the expansion of plot limits, showing area outside the plot, e.g. if showing a ship track as a gps, and then an actual gps to show the ocean boundary. The value of expand is ignored if either xlim

mgp

3-element numerical vector to use for par(mgp), and also for par(mar), computed from this. The default is tighter than the R default, in order to use more space for the data and less for the axes.

mar

value to be used with par("mar").

bg

optional colour to be used for the background of the map. This comes in handy for drawing insets (see details).

axes

boolean, set to TRUE to plot axes.

cex.axis

value for axis font size factor.

add

boolean, set to TRUE to draw the gps on an existing plot. Note that this retains the aspect ratio of that existing plot, so it is important to set that correctly, e.g. with asp=1/cos(lat * pi / 180), where

inset

set to TRUE for use within plotInset. The effect is to prevent the present function from adjusting margins, which is necessary because margin adjustment is the basis for the meth

geographical

flag indicating the style of axes. If geographical=0, the axes are conventional, with decimal degrees as the unit, and negative signs indicating the southern and western hemispheres. If geographical=1, the sig

debug

set to TRUE to get debugging information during processing.

...

optional arguments passed to plotting functions. For example, set yaxp=c(-90,90,4) for a plot extending from pole to pole.

Value

• None.

Details

This function plots a gps object. An attempt is made to use the whole space of the plot, and this is done by limiting either the longitude range or the latitude range, as appropriate, by modifying the eastern or northern limit, as appropriate.

To get an inset map inside another map, draw the first map, do par(new=TRUE), and then call plot.gps with a value of mar that moves the inset plot to a desired location on the existing plot, and with bg="white".

See Also

The documentation for gps-class explains the structure of gps objects, and also outlines the other functions dealing with them.

Examples

Run this code

library(oce)
gps <- read.oce("~/Dropbox/dalwhoi.gpx")
plot(gps)
lines(coastlineWorld[["longitude"]], coastlineWorld[["latitude"]])

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