btb {spatstat.data}

Bovine Tuberculosis Data

Description

Geospatial data of 873 farm locations with detected bovine tuberculosis in Cornwall, UK, over the years 1989-2002. This data-set was first analysed in Diggle, Zheng and Durr (2005).

Usage

data(btb)

Format

Loading this dataset supplies the point pattern btb and the additional object btb.extra.

btb is a marked point pattern (see ppp.object) containing 873 points. Its spatial coordinates are Eastings and Northings in kilometres giving the farm locations. It has two columns of marks:

year	Year of detection: a factor with levels 1989 to 2002
spoligotype	Spoligotype of tuberculosis: a factor with four levels “9”, “12”, “15”, “20”

Loading the dataset btb will also load the object btb.extra containing additional data. This is a list (of class "solist") containing two elements,

standard

The standard version of the BTB dataset used in many publications. This is a marked point pattern, identical to btb except that its window of observation is a slightly larger and simpler polygon than the window of btb.

full

A more extensive dataset compiled from files supplied by Professor Diggle. This is a marked point pattern, identical to standard except that it includes 46 additional farm locations where bovine tuberculosis was detected, but where the spoligotype was not one of the four common spoligotypes. There are 919 data points altogether. The attribute attr(full, "retained") is a logical vector indicating which of the points in full was retained or deleted to obtain standard.

Source

Professor Peter Diggle.

Roger Sainsbury of the UK's State Veterinary Service helped to collect the data-set. Jackie Inwald and Si Palmer of the Department of Bacterial Diseases, Veterinary Laboratories Agency, Weybridge, UK carried out the spoligotyping.

Peter Diggle supplied the point coordinates, spoligotype data and year data, and the coordinates of the window used in btb.extra.

Tilman Davies drew the finer window used in btb.

References

Diggle, P.J., Zheng, P. and Durr, P. (2005) Nonparametric estimation of spatial segregation in a multivariate point process: bovine tuberculosis in Cornwall, UK. Applied Statistics, 54, 645–658.

Examples

  if(require(spatstat.geom)) {
    summary(btb)
    plot(subset(btb, select=spoligotype), cols=2:5)
  }