SpatialPolygonsDataFrame-class {sp} | R Documentation

## Class "SpatialPolygonsDataFrame"

### Description

class to hold polygons with attributes

### Objects from the Class

Objects can be created by calls to the function SpatialPolygonsDataFrame

### Slots

`data`:

  Object of class `"data.frame"`; attribute table

`polygons`:

  Object of class `"list"`; see SpatialPolygons-class

`plotOrder`:

  Object of class `"integer"`; see SpatialPolygons-class

`bbox`:

  Object of class `"matrix"`; see Spatial-class

`proj4string`:

  Object of class `"CRS"`; see CRS-class

### Extends

Class `"SpatialPolygons"`, directly. Class `"Spatial"`, by class `"SpatialPolygons"`.

### Methods

Methods defined with class "SpatialPolygonsDataFrame" in the signature:

[

  `signature(x = "SpatialPolygonsDataFrame")`: select subset of (sets of) polygons; NAs are not permitted in the row index

rbind

  `signature(object = "SpatialPolygonsDataFrame")`: rbind-like method, see notes below

### Note

`SpatialPolygonsDataFrame` with default ID matching checks the data frame row names against the Polygons ID slots. They must then agree with each other, and be unique (no Polygons objects can share IDs); the data frame rows will be re-ordered if needed to match the Polygons IDs..

If you want to `rbind` objects with duplicated IDs, see`spChFIDs`.

### Author(s)

Roger Bivand

### See Also

SpatialPolygons-class

### Examples

    # simple example, from scratch:
    Sr1 = Polygon(cbind(c(2,4,4,1,2),c(2,3,5,4,2)))
    Sr2 = Polygon(cbind(c(5,4,2,5),c(2,3,2,2)))
    Sr3 = Polygon(cbind(c(4,4,5,10,4),c(5,3,2,5,5)))
    Sr4 = Polygon(cbind(c(5,6,6,5,5),c(4,4,3,3,4)), hole = TRUE)

    Srs1 = Polygons(list(Sr1), "s1")
    Srs2 = Polygons(list(Sr2), "s2")
    Srs3 = Polygons(list(Sr3, Sr4), "s3/4")
    SpP = SpatialPolygons(list(Srs1,Srs2,Srs3), 1:3)
    plot(SpP, col = 1:3, pbg="white")

    grd <- GridTopology(c(1,1), c(1,1), c(10,10))
    polys <- as(grd, "SpatialPolygons")
    centroids <- coordinates(polys)
    x <- centroids[,1]
    y <- centroids[,2]
    z <- 1.4 + 0.1*x + 0.2*y + 0.002*x*x
    ex_1.7 <- SpatialPolygonsDataFrame(polys,
     data=data.frame(x=x, y=y, z=z, row.names=row.names(polys)))
    brks <- quantile(z, seq(0,1,1/7))
    cols <- grey((length(brks):2)/length(brks))
    dens <- (2:length(brks))*3
    plot(ex_1.7, col=cols[findInterval(z, brks, all.inside=TRUE)])
    plot(ex_1.7, density=dens[findInterval(z, brks, all.inside=TRUE)])

[Package sp version 1.2-2 Index]