gmt (version 1.0-0)

psbar: Add Bars to GMT Mercator Map

Description

Call GMT to add bars to the active map and save in postscript format. This function does the necessary calculations to render bars in standard height given a Mercator-projected map. It is not intended for other projections.

Usage

psbar(x, cmd="-JM -R -W1p -G180 -O -K", file=options("gmt.file"), ref=0,
      digits=options("digits"))

Arguments

x

data frame, matrix, or filename containing the data to be plotted

cmd

string of arguments passed to psxy

file

filename where the map is saved

ref

reference latitude where Height=1 renders a bar 1 degree high

digits

precision used when rounding the geographic coordinates

Value

• Null, but the map is annotated and saved in postscript format. As a side product, a temporary file lastBAR.gmt is saved in the working directory.

Details

The data are arranged in four columns: Lon, Lat, Width, and Height, in that order. See the GMT documentation for details on psxy and other GMT commands.

References

Wessel, P. and W.H.F. Smith. 2004. The Generic Mapping Tools: Technical reference and cookbook. Version 4. Available at http://gmt.soest.hawaii.edu/gmt/doc/pdf/GMT$\_$Docs.pdf.

See Also

gmt initializes the GMT session, pscoast draws a map, psxy, pstext and psbar annotate the map, and psclose finalizes the postscript file. See r2gmt for valid data file format when argument x is a filename.

Examples

gmt(demo.par)
pscoast(demo.coast)
psxy(demo.xy)
pstext(demo.text)
psbar(demo.bar, ref=64)
psclose()