hexbin: hexTapply – R documentation

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hexTapply

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

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)

hexbin

Hexagonal Binning Routines

v1.28.2

GPL-2

Authors

Dan Carr <dcarr@voxel.galaxy.gmu.edu>, ported by Nicholas Lewin-Koh and Martin Maechler <maechler@stat.math.ethz.ch>, contains copies of lattice functions written by Deepayan Sarkar <deepayan.sarkar@r-project.org>

Initial release