SpatialPixels {sp} | R Documentation

## define spatial grid

### Description

defines spatial grid by offset, cell size and dimensions

### Usage

    GridTopology(cellcentre.offset, cellsize, cells.dim)
    SpatialPixels(points, tolerance = 10 * .Machine$double.eps)
    SpatialGrid(grid, proj4string = CRS(as.character(NA)))
    coordinatevalues(obj)
    points2grid(points, tolerance)
    getGridIndex(cc, grid, all.inside = TRUE)
    getGridTopology(obj)
    areaSpatialGrid(obj)

### Arguments

`cellcentre.offset` | numeric; vector with the smallest coordinates for each dimension
`cellsize` | numeric; vector with the cell size in each dimension
`cells.dim` | integer; vector with number of cells in each dimension
`points` | coordinates, object of class SpatialPoints-class
`grid` | grid topology; object of class GridTopology-class
`tolerance` | precision, used to which extent points are exactly on a grid
`proj4string` | object of class CRS-class
`obj` | object of class or deriving from SpatialGrid-class
`cc` | numeric matrix with coordinates
`all.inside` | logical; if TRUE and `cc` points fall outside the grid area, an error message is generated; if FALSE, NA values are generated for such points

### Value

GridTopology returns a value of class GridTopology-class; SpatialGrid returns an object of class SpatialGrid-class
`coordinatevalues` returns a list with the unique x-coordinates, the unique y-coordinate, etc. instead of the coordinates of all grid cells
SpatialGrid returns an object of class SpatialGrid-class.
points2grid returns the GridTopology-class from a set of points.
getGridIndex finds the index of a set of point coordinates in a given grid topology, and depending on `all.inside` setting, generates NA or an error message if points are outside the grid domain.
getGridTopology returns the slot of class GridTopology-class from obj.
areaSpatialGrid returns the spatial area of (the non-missing valued cells of) the grid. For objects of class SpatialGridDataFrame-class the area refers to cells where any (one or more) of the attribute columns are non-missing valued.

### Note

SpatialGrid stores grid topology and may or may not store the coordinates of the actual points, which may form a subset of the full grid. To find out or change this, see fullgrid.

### Author(s)

Edzer J. Pebesma, e.pebesma@geo.uu.nl

### References

### See Also

SpatialGrid-class, SpatialGridDataFrame-class,

### Examples

    x = GridTopology(c(0,0), c(1,1), c(5,4))
    class(x)
    x
    summary(x)
    coordinates(x)
    coordinates(GridTopology(c(0,0), c(1,1), c(5,4)))
    coordinatevalues(x)

[Package sp version 0.7-12 Index]