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: begin{enumerate}

- `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.
- `gambia.borders`
  A data frame with 2 variables:
  x
    x-coordinate of the country borders.
  y
    y-coordinate of the country borders.

  end{enumerate}

  ### 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

      data(gambia)
      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 1.5-7 Index]