Interface between sp and bnd format {BayesX}

Convert sp and bnd format into each other

Description

Convert geographical information objects of class "SpatialPolygons" (or specializations) from R-package sp to objects of class "bnd" from R-package BayesX and vice versa.

Usage

sp2bnd(spObject, regionNames, height2width, epsilon)
bnd2sp(bndObject)

Arguments

spObject

object of class "SpatialPolygons" (or specializations)

regionNames

character vector of region names (parallel to the Polygons list in spObject), defaults to the IDs

height2width

ratio of total height to width, defaults to the bounding box values

epsilon

how much can two polygons differ (in maximum squared Euclidean distance) and still match each other?, defaults to machine precision

bndObject

object of class "bnd"

Value

Equivalent object in the other format.

Author(s)

Daniel Sabanes Bove

See Also

nb2gra, gra2nb for conversion between the neighborhood structure formats and read.bnd, write.bnd for the interface to the BayesX files.

Examples

## Not run: ## bnd to sp:
germany <- read.bnd(system.file("examples/germany2001.bnd", package="BayesX"))
spGermany <- bnd2sp(germany)

## plot the result together with the neighborhood graph
library(sp)
plot(spGermany)
library(spdep)
nbGermany <- poly2nb(spGermany)
plot(nbGermany, coords=coordinates(spGermany), add=TRUE)

## example with one region inside another
spExample <- spGermany[c("7211", "7235"), ]
plot(spExample)
plot(poly2nb(spExample), coords=coordinates(spExample), add=TRUE)

## now back from sp to bnd:
bndGermany <- sp2bnd(spGermany)
drawmap(map=bndGermany)

## compare names and number of polygons
stopifnot(identical(names(bndGermany),
                    names(germany)),
          identical(length(bndGermany),
                    length(germany)))

## compare contains-relations
surrounding <- attr(bndGermany, "surrounding")
whichInner <- which(sapply(surrounding, length) > 0L)
bndContainsData <- data.frame(inner=names(bndGermany)[whichInner],
                              outer=unlist(surrounding))

surrounding <- attr(germany, "surrounding")
whichInner <- which(sapply(surrounding, length) > 0L)
originalContainsData <- data.frame(inner=names(germany)[whichInner],
                                   outer=unlist(surrounding))

stopifnot(all(bndContainsData[order(bndContainsData$inner), ] ==
              originalContainsData[order(originalContainsData$inner), ]))

## End(Not run)