as.SpatialPolygons.GridTopology {sp} | R Documentation

## Make SpatialPolygons object from GridTopology object

### Description

Converts grids of regular rectangles into a `SpatialPolygons` object, which can be transformed to a different projection or datum. The function is not suitable for high-resolution grids. The ordering of the grid cells is as in `coordinates()` of the same object, and is reported by `IDvaluesGridTopology`.

### Usage

    as.SpatialPolygons.GridTopology(grd, proj4string = CRS(as.character(NA)))
    IDvaluesGridTopology(obj)

### Arguments

`grd,obj` | `GridTopology` object
`proj4string` | projection string of class CRS

### Value

`as.SpatialPolygons.GridTopology` returns a `SpatialPolygons` object; `IDvaluesGridTopology` returns a character vector with the `GridTopology` object column and row indices.

### See Also

`GridTopology`, `SpatialPolygons`

### Examples

    grd <- GridTopology(cellcentre.offset=c(-175,55), cellsize=c(10,10), cells.dim=c(4,4))
    SpP_grd <- as.SpatialPolygons.GridTopology(grd)
    plot(SpP_grd)
    text(getSpPPolygonsLabptSlots(SpP_grd), getSpPPolygonsIDSlots(SpP_grd), cex=0.5)
    trdata <- data.frame(A=rep(c(1,2,3,4), 4), B=rep(c(1,2,3,4), each=4), row.names=getSpPPolygonsIDSlots(SpP_grd))
    SpPDF <- SpatialPolygonsDataFrame(SpP_grd, trdata)
    spplot(SpPDF)

[Package sp version 0.7-12 Index]