hexTapply {hexbin} | R Documentation

## Apply function to data from each hexagon bin.

### Description

A wrapper for tapply except that it operates with each hexagon bin being the category. The function operates on the data associated on the points from each bin.

### Usage

    hexTapply(hbin, dat, FUN = sum, ..., simplify=TRUE)

### Arguments

`hbin` | a object of class `"hexbin"`, typically produced by `hexbin(*)`.
`dat` | A vector of data the same length as `hbin@cID`
`FUN` | the function to be applied. In the case of functions like `+`, `%*%`, etc., the function name must be quoted. If `FUN` is `NULL`, tapply returns a vector which can be used to subscript the multi-way array `tapply` normally produces.
`...` | optional arguments to `FUN`.
`simplify` | If `FALSE`, `tapply` always returns an array of mode `"list"`. If `TRUE` (the default), then if `FUN` always returns a scalar, `tapply` returns an array with the mode of the scalar.

### Details

This function is a wrapper for tapply, except that the cell id is always the categorical variable. This function is specifically good for adding variables to the cAtt slot of a hexbin object or for plotting a third variable in a hexagon plot. See below for examples.

### Value

Returns a vector of the result of 'FUN' as in `tapply`. See `tapply` for detailed description of output.

### Author(s)

Nicholas Lewin-Koh

### See Also

`tapply`,`hexbin`

### Examples

      data(NHANES)
      hbin<-hexbin(log(NHANES$Diet.Iron+1),log(NHANES$BMI),xbins=25,IDs=TRUE)
      hvp<-plot(hbin)
      mtrans<-hexTapply(hbin,NHANES$Transferin,median,na.rm=TRUE)
      pushHexport(hvp$plot.vp)
      grid.hexagons(hbin,style='lattice',pen=0,border='red',use.count=FALSE,
    cell.at=mtrans)

[Package hexbin version 1.4.0 Index]