lattice (version 0.20-41)

# G_banking: Banking

## Description

Calculates banking slope

## Usage

`banking(dx, dy)`

## Arguments

dx, dy

vector of consecutive x, y differences.

## Details

`banking` is the banking function used when `aspect = "xy"` in high level Trellis functions. It is usually not very meaningful except with `xyplot`. It considers the absolute slopes (based on `dx` and `dy`) and returns a value which when adjusted by the panel scale limits will make the median of the above absolute slopes correspond to a 45 degree line.

This function was inspired by the discussion of banking in the documentation for Trellis Graphics available at Bell Labs' website (see `Lattice`), but is most likely identical to an algorithm described by Cleveland et al (see below). It is not clear (to the author) whether this is the algorithm used in S-PLUS. Alternative banking rules, implemented as a similar function, can be used as a drop-in replacement by suitably modifying `lattice.options("banking")`.

## References

Cleveland, William S. and McGill, Marylyn E. and McGill, Robert (1988) “The Shape Parameter of a Two-variable Graph”, Journal of the American Statistical Association, 83, 289--300.

## See Also

`Lattice`, `xyplot`

## Examples

```# NOT RUN {
## with and without banking

plot <- xyplot(sunspot.year ~ 1700:1988, xlab = "", type = "l",
scales = list(x = list(alternating = 2)),
main = "Yearly Sunspots")
print(plot, position = c(0, .3, 1, .9), more = TRUE)
print(update(plot, aspect = "xy", main = "", xlab = "Year"),
position = c(0, 0, 1, .3))

## cut-and-stack plot (see also xyplot.ts)

xyplot(sunspot.year ~ time(sunspot.year) | equal.count(time(sunspot.year)),
xlab = "", type = "l", aspect = "xy", strip = FALSE,
scales = list(x = list(alternating = 2, relation = "sliced")),
as.table = TRUE, main = "Yearly Sunspots")

# }
```