R: Class "Spatial"

Spatial-class {sp} | R Documentation

## Class "Spatial"

### Description

An abstract class from which useful spatial classes are derived

### Usage

    Spatial(bbox, proj4string = CRS(as.character(NA)))
    ## S3 method for class 'Spatial'
    subset(x, subset, select, drop = FALSE, ...)

### Arguments

`bbox` | a bounding box matrix
`proj4string` | a CRS object
`x` | object of class Spatial
`subset` | see subset.data.frame
`select` | see subset.data.frame
`drop` | see subset.data.frame
`...` | passed through

### Objects from the Class

are never to be generated; only derived classes can be meaningful

### Slots

`bbox`:

  Object of class `"matrix"`; 2-column matrix holding the minimum in first and maximum in second column for the x-coordinate (first row), y-coordinate (second row) and optionally, for points and grids only, further coordinates. The constructed Spatial object will be invalid if any bbox values are NA or infinite. The column names must be `c("min", "max")`

`proj4string`:

  Object of class `"CRS"`; holding a valid proj4 string, which can be used for unprojecting or reprojecting coordinates; it is initialised to NA. Other strings are checked for validity in the rgdal package, but attempts to assign a string containing "longlat" to data extending beyond longitude [-180, 360] or lattitude [-90, 90] will be stopped or warned, use `set_ll_warn` to warn rather than stop, and `set_ll_TOL` to change the default tolerance for the range exceedance tests.

### Methods

bbox

  `signature(obj = "Spatial")`: retrieves the bbox element

dimensions

  `signature(obj = "Spatial")`: retrieves the number of spatial dimensions spanned

gridded

  `signature(obj = "Spatial")`: logical, tells whether the data is on a regular spatial grid

plot

  `signature(x = "Spatial", y = "missing")`: plot method for spatial objects; does nothing but setting up a plotting region choosing a suitable aspect if not given(see below), colouring the plot background using either a bg= argument or par("bg"), and possibly drawing axes.

summary

  `signature(object = "Spatial")`: summarize object

`$`

  retrieves attribute column

`$<-`

  sets or replaces attribute column, or promote a geometry-only object to an object having an attribute

### plot method arguments

The plot method for “Spatial” objects takes the following arguments:

x

  object of class Spatial

xlim

  default NULL; the x limits (x1, x2) of the plot

ylim

  default NULL; the y limits of the plot

asp

  default NA; the y/x aspect ratio

axes

  default FALSE; a logical value indicating whether both axes should be drawn

bg

  default `par("bg")`; colour to be used for the background of the device region

xaxs

  The style of axis interval calculation to be used for the x-axis

yaxs

  The style of axis interval calculation to be used for the y-axis

lab

  A numerical vector of the form `c(x, y, len)` which modifies the default way that axes are annotated

setParUsrBB

  default FALSE; set the `par` “usr” bounding box; see below

bgMap

  object of class `ggmap`, or returned by function `RgoogleMaps::GetMap`

expandBB

  numeric; factor to expand the plotting region default: `bbox(x)` with on each side (1=below, 2=left, 3=above and 4=right); defaults to `c(0,0,0,0)`; setting `xlim` or `ylim` overrides this.

...

  passed through

### Warning

this class is not useful in itself, but all spatial classes in this package derive from it

### Note

The default aspect for map plots is 1; if however data are not projected (coordinates are longlat), the aspect is by default set to 1/cos(My * pi)/180) with My the y coordinate of the middle of the map (the mean of ylim, which defaults to the y range of bounding box).

The argument `setParUsrBB` may be used to pass the logical value `TRUE` to functions within `plot.Spatial`. When set to `TRUE`, par(“usr”) will be overwritten with `c(xlim, ylim)`, which defaults to the bounding box of the spatial object. This is only needed in the particular context of graphic output to a specified device with given width and height, to be matched to the spatial object, when using par(“xaxs”) and par(“yaxs”) in addition to `par(mar=c(0,0,0,0))`.

### Author(s)

r-spatial team; Edzer Pebesma, edzer.pebesma@uni-muenster.de Roger Bivand, Barry Rowlingson, Virgilio G\'omez-Rubio

### See Also

`SpatialPoints-class`, `SpatialGrid-class`, `SpatialPointsDataFrame-class`, `SpatialGridDataFrame-class`

[Package sp version 1.3-2 Index]