R: Apply a function to matrix data

binApply2D {oce}

R Documentation

Apply a function to matrix data

Description

The function FUN is applied to f in bins specified by xbreaks and ybreaks. (If FUN is mean(), consider using binMean2D() instead, since it should be faster.)

Usage

binApply2D(x, y, f, xbreaks, ybreaks, FUN, ...)

Arguments

`x`	a vector of numerical values.
`y`	a vector of numerical values.
`f`	a vector of data to which the elements of `FUN` may be supplied
`xbreaks`	values of `x` at the boundaries between the bins; calculated using `pretty()` if not supplied.
`ybreaks`	as `xbreaks`, but for `y`.
`FUN`	univariate function that is applied to the `f` data within any given bin
`...`	arguments to pass to the function `FUN`

Value

A list with the following elements: the breaks in x and y (i.e. xbreaks and ybreaks), the break mid-points (i.e. xmids and ymids), and a matrix containing the result of applying FUN() to the f values, as subsetted by these breaks.

Author(s)

Dan Kelley

Examples

library(oce)

## secchi depths in lat and lon bins
if (requireNamespace("ocedata", quietly=TRUE)) {
    data(secchi, package="ocedata")
    ## Note that zlim is provided to the colormap(), to prevent a few
    ## points from setting a very wide scale.
    cm <- colormap(z=secchi$depth, col=oceColorsViridis, zlim=c(0, 15))
    par(mar=c(2, 2, 2, 2))
    drawPalette(colormap=cm, zlab="Secchi Depth")
    data(coastlineWorld)
    mapPlot(coastlineWorld, longitudelim=c(-5, 20), latitudelim=c(50, 66),
      grid=5, col='gray', projection="+proj=lcc +lat_1=50 +lat_2=65")
    bc <- binApply2D(secchi$longitude, secchi$latitude,
                     pretty(secchi$longitude, 80),
                     pretty(secchi$latitude, 40),
                     f=secchi$depth, FUN=mean)
    mapImage(bc$xmids, bc$ymids, bc$result, zlim=cm$zlim, col=cm$zcol)
    mapPolygon(coastlineWorld, col="gray")
}

[Package oce version 1.2-0 Index]