oce (version 0.9-18)

coastline-class: Class to store coastline data

Description

Class to store coastline data, with standard slots metadata (containing fillable and filename), data (containing longitude and latitude) and processingLog.

Methods

Extracting values{Positional data may be accessed as e.g. coastline[["longitude"]] or coastline[["latitude"]], with abbreviations (e.g. coastline[["lo"]]) being permitted so long as they are distinct. However, metadata must be named in full.}

Assigning values{Latitude may be changed with e.g. coastline[["longitude"]] <- value, and of course the same can be done for latitude.}

Overview of contents{The show method (e.g. show(coastline)) displays information about the object.}

Data sources

The NOAA website http://www.ngdc.noaa.gov/mgg/shorelines/shorelines.html is a popular starting point for coastline data. One assumes the data have some sort of authority, being provided by a national organization. Another source for coastline data is http://www.naturalearthdata.com, which provides world datasets in a variety of resolutions. Another advantage of the Natural Earth is that it provides data not just for coastlines, but also for rivers, lakes, glaciated areas, and place names. The oce dataset named coastlineWorld came from Natural Earth.

Archiving your own coastline files

The present package provides a coarse-resolution world coastline in coastlineWorld, and the ocedata package provides two alternatives at world scale. It is common for users to want to use other coastlines, but CRAN policies do not allow packages with tens of megabytes of such data. Users should download such data and store them in .rda files with e.g., for a shapefile-formate file is named "mycoastline.shp" to be stored in a directory named /data/coastlines, one might do as follows.

mycoastline <- oce::read.oce("mycoastline.shp") save(mycoastline, file="/data/coastlines/mycoastline.rda") tools::resaveRdaFiles("/data/coastlines/mycoastline.rda", compress="auto") after which accessing the saved mycoastline dataset is as simple as writing load("/data/coastlines/mycoastline.rda") Note: it is important to save the coastline with a new name, to avoid conflicts with coastlineWorld in the present package, and coastlineWorldMedium and coastlineWorldFine in the ocedata package.

See Also

Use as.coastline to convert data to this form, read.coastline to read data in various formats, and plot.coastline to plot coastlines.