huePosition {aqp} R Documentation

## Munsell Hue Reference and Position Searching

### Description

The 40 Munsell hues are typically arranged from 5R to 2.5R moving clock wise on the unit circle. This function matches a vector of hues to positions on that circle, with options for setting a custom origin or search direction.

This function is fully vectorized.

### Usage

```huePosition(
x,
returnHues = FALSE,
includeNeutral = FALSE,
origin = "5R",
direction = c("cw", "ccw")
)
```

### Arguments

 `x` character vector of hues, e.g. c('10YR', '5YR'), optional if `returnHues = TRUE` `returnHues` logical, should the full set of Munsell hues be returned? See details. `includeNeutral` logical, add 'N' to the end of the full set of Munsell hues `origin` hue to be used as the starting point for position searches (position 1) `direction` indexing direction, should be `cw` (clock wise) or `ccw` (counter-clock wise)

### Value

A vector of integer hue positions is returned, of the same length and order as `x`. If `returnHues = TRUE`, then all hue names and ordering are returned and `x` is ignored.

D.E. Beaudette

### References

https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcs142p2_053569

Munsell book of color. 1976. Macbeth, a Division of Kollmorgen Corp., Baltimore, MD.

### Examples

```
# get hue ordering for setting levels of a factor
huePosition(returnHues = TRUE)

# get hue ordering including N (neutral)
huePosition(returnHues = TRUE, includeNeutral = TRUE)

# get position of the '10YR' hue, relative to standard origin of '5R'
# should be 7
huePosition(x = '10YR')

# get position of the '10YR' hue, relative to standard origin of '5YR'
# should be 3
huePosition(x = '10YR', origin = '5YR')

# visualize
op <- par(mar = c(0, 0, 0, 0), fg = 'white', bg = 'black')

huePositionCircle(huePosition(returnHues = TRUE, origin = '5YR'))

par(op)

```

[Package aqp version 1.40 Index]