columb {mgcv} | R Documentation

## Reduced version of Columbus OH crime data

### Description

By district crime data from Columbus OH, together with polygons describing district shape. Useful for illustrating use of simple Markov Random Field smoothers.

### Usage

    data(columb)
    data(columb.polys)

### Format

`columb` is a 49 row data frame with the following columns

area

  land area of district

home.value

  housing value in 1000USD.

income

  household income in 1000USD.

crime

  residential burglaries and auto thefts per 1000 households.

open.space

  measure of open space in district.

district

  code identifying district, and matching `names(columb.polys)`.

`columb.polys` contains the polygons defining the areas in the format described below.

### Details

The data frame `columb` relates to the districts whose boundaries are coded in `columb.polys`. `columb.polys[[i]]` is a 2 column matrix, containing the vertices of the polygons defining the boundary of the ith district. `columb.polys[[2]]` has an artificial hole inserted to illustrate how holes in districts can be spefified. Different polygons defining the boundary of a district are separated by NA rows in `columb.polys[[1]]`, and a polygon enclosed within another is treated as a hole in that region (a hole should never come first). `names(columb.polys)` matches `columb$district` (order unimportant).

### Source

The data are adapted from the `columbus` example in the `spdep` package, where the original source is given as:

Anselin, Luc. 1988. Spatial econometrics: methods and models. Dordrecht: Kluwer Academic, Table 12.1 p. 189.

### Examples

    ## see ?mrf help files

[Package mgcv version 1.8-12 Index]