R: Subset a Coastline Object

subset,coastline-method {oce} | R Documentation

## Subset a Coastline Object

### Description

Subsets a coastline object according to limiting values for longitude and latitude. This uses functions in the raster package for some calculations, and so it will fail unless that package is installed.

### Usage

    ## S4 method for signature 'coastline'
    subset(x, subset, ...)

### Arguments

`x` | a coastline object.
`subset` | An expression indicating how to subset `x`. See “Details”.
`...` | optional additional arguments, the only one of which is considered is one named `debug`, an integer that controls the level of debugging. If this is not supplied, `debug` is assumed to be 0, meaning no debugging. If it is 1, the steps of determining the bounding box are shown. If it is 2 or larger, then additional processing steps are shown, including the extraction of every polygon involved in the final result.

### Details

As illustrated in the “Examples”, `subset` must be an expression that indicates limits on `latitude` and `longitude`. The individual elements are provided in R notation, not mathematical notation (i.e. `30<latitude<60` would not work). Ampersands must be used to combine the limits. The simplest way to understand this is to copy the example directly, and then modify the stated limits. Note that `>` comparison is not permitted, and that `<` is converted to `<=` in the calculation. Similarly, `&&` is converted to `&`. Spaces in the expression are ignored. For convenience, `longitude` and and `latitude` may be abbreviated as `lon` and `lat`, as in the “Examples”.

### Value

A `coastline` object.

### Author(s)

Dan Kelley

### See Also

Other things related to coastline data: `[[,coastline-method`, `[[<-,coastline-method`, `as.coastline()`, `coastline-class`, `coastlineBest()`, `coastlineCut()`, `coastlineWorld`, `download.coastline()`, `plot,coastline-method`, `read.coastline.openstreetmap()`, `read.coastline.shapefile()`, `summary,coastline-method`

Other functions that subset oce objects: `subset,adp-method`, `subset,adv-method`, `subset,amsr-method`, `subset,argo-method`, `subset,cm-method`, `subset,ctd-method`, `subset,echosounder-method`, `subset,lobo-method`, `subset,met-method`, `subset,oce-method`, `subset,odf-method`, `subset,rsk-method`, `subset,sealevel-method`, `subset,section-method`, `subset,topo-method`, `subset,xbt-method`

### Examples

    library(oce)
    data(coastlineWorld)
    ## Subset to a box centred on Nova Scotia, Canada
    if (requireNamespace("sf")) {
        cl <- subset(coastlineWorld, -80<lon & lon<-50 & 30<lat & lat<60)
        ## The plot demonstrates that the trimming is as requested.
        plot(cl, clon=-65, clat=45, span=6000)
        rect(-80, 30, -50, 60, bg="transparent", border="red")
    }

[Package oce version 1.2-0 Index]