R: Gambia Malaria Data

gambia {geoR} | R Documentation

## Gambia Malaria Data

### Description

Malaria prevalence in children recorded at villages in The Gambia, Africa.

### Usage

    data(gambia)

### Format

Two objects are made available:

1. `gambia`
   A data frame with 2035 observations on the following 8 variables.

   x

     x-coordinate of the village (UTM).

   y

     y-coordinate of the village (UTM).

   pos

     presence (1) or absence (0) of malaria in a blood sample taken from the child.

   age

     age of the child, in days

   netuse

     indicator variable denoting whether (1) or not (0) the child regularly sleeps under a bed-net.

   treated

     indicator variable denoting whether (1) or not (0) the bed-net is treated (coded 0 if netuse=0).

   green

     satellite-derived measure of the green-ness of vegetation in the immediate vicinity of the village (arbitrary units).

   phc

     indicator variable denoting the presence (1) or absence (0) of a health center in the village.

2. `gambia.borders`
   A data frame with 2 variables:

   x

     x-coordinate of the country borders.

   y

     y-coordinate of the country borders.

### References

Thomson, M., Connor, S., D Alessandro, U., Rowlingson, B., Diggle, P., Cresswell, M. & Greenwood, B. (1999). Predicting malaria infection in Gambian children from satellite data and bednet use surveys: the importance of spatial correlation in the interpretation of results. American Journal of Tropical Medicine and Hygiene 61: 2–8.

Diggle, P., Moyeed, R., Rowlingson, B. & Thomson, M. (2002). Childhood malaria in The Gambia: a case-study in model-based geostatistics, Applied Statistics.

### Examples

    plot(gambia.borders, type="l", asp=1)
    points(gambia[,1:2], pch=19)
    # a built-in function for a zoomed map
    gambia.map()
    # Building a "village-level" data frame
    ind <- paste("x",gambia[,1], "y", gambia[,2], sep="")
    village <- gambia[!duplicated(ind),c(1:2,7:8)]
    village$prev <- as.vector(tapply(gambia$pos, ind, mean))
    plot(village$green, village$prev)

[Package geoR version 1.7-5.2 Index]