[
, [[
, $
, names, dim, summary, and a number of
methods specific to spatial data handling.External packages that depend on sp will provide importing and exporting from and to external GIS formats, e.g. through GDAL, OGR or shapelib.
In addition, this package tries to provide convenient methods to print, summarize and plot such spatial data.
This CRS can be a character string describing a reference system in
a way understood by the PROJ.4 projection library, or a (character)
missing value. The package spproj needs to be available if one wants to
work with (non-missing valued) coordinate reference systems; this
packages needs, but does not contain the PROJ.4 external library, and
is therefore not available for Windows R versions on CRAN
Spatial
, which only
provides a bounding box and a CRS. This class has no useful instances, but
useful derived classes. SpatialPoints extends Spatial and has coordinates. The method coordinates extracts the numeric matrix with coordinates from an object of class SpatialPoints, or from other (possibly derived) classes that have points.
Objects of class SpatialGrid points on a regular grid. Either a full grid is stored or a partial grid (i.e., only the non-missing valued cells); calling coordinates on them will give the coordinates for the grid cells.
SpatialPoints, SpatialCell and SpatialGridded can be of arbitray dimension, although most of the effort is in making them work for two dimensional data.
SpatialLines provides lines, and SpatialRings provides polygons, i.e., lines that end where they start and do not intersect with itself. SpatialLines and SpatialRings only have two-dimensional data.
SpatialPointsDataFrame extends SpatialPoints with a data slot, having a data.frame with attribute data. Similarly, SpatialCellDataFrame, SpatialLinesDataFrame, SpatialPolygonsDataFrame extend the primary spatial information with attribute data.
GDAL and OGR: