read.coastline {oce}R Documentation

Scan a coastline data file

Description

Read a coastline file in mapgen, matlab, or Splus format

Usage

read.coastline(file,type=c("R","S","mapgen"),debug=FALSE, log.action)

Arguments

file name of file containing coastline data.
type type of file, one of "R", "S", or "mapgen"
debug set to TRUE to print information about the header, etc.
log.action if provided, the action item to be stored in the log. (Typically only provided for internal calls; the default that it provides is better for normal calls by a user.)

Details

The S and R formats are identical, and consist of two columns, lon and lat, with land-jump segments separated by lines with two NAs.

The MapGen format is of the form

# -b
-16.179081      28.553943
-16.244793      28.563330
BUG: the 'arc/info ungenerate' format is not yet understood.

Value

An object of class "coastline", which is a list containing

data a list containing
longitude
the longitude in decimal degrees positive east of Greenwich.
latitude
the latitude in decimal degrees positive north of the equator.
metadata a NULL item that may be used in a future version.
processing.log A processing log, in the standard oce format.

Author(s)

Dan Kelley

References

The NOAA site http://www.ngdc.noaa.gov/mgg/shorelines/shorelines.html is a good source for coastline data files.

See Also

The generic function read.oce provides an alternative to this. Coastlines may be created from latitude/longitude pairs with as.coastline, summarized with summary.coastline and plotted with plot.coastline.

Examples

## Not run: 
library(oce)
cl <- read.coastline("7404.dat")
# If no plot yet:
plot(cl)
# To add to an existing plot:
lines(cl$data$longitude, cl$data$latitude)
# Note: another trick is to do something like the following,
# to get issues of whether longitude is defined in (-180,180)
# or (0,360)
lines(cl$datas$longitude, cl$data$latitude)
lines(cl$data$longitude-360, cl$data$latitude)
## End(Not run)

[Package oce version 0.1-76 Index]