Class "Spatial"

Description

An abstract class from which useful spatial classes are derived

Usage

Spatial(bbox, proj4string = CRS(as.character(NA)))

Arguments

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.

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

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 Rowlinson, Virgilio G'omez-Rubio

See Also

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