define_cat: Creates a category object
In ropensci/pixelclasser: Classifies Image Pixels by Colour

Description Usage Arguments Details Value See Also Examples

Creates an object of class pixel_cat, which contains a list of objects of class pixel_subcat.

1	define_cat(cat_name, cat_colour, ...)

`cat_name`	a character string containing the name of the category.
`cat_colour`	a character string defining the colour to paint the pixels with when creating a classified picture.
`...`	a list of `pixel_subcat` objects, or `pixel_rule` objects in case that subcategories are not needed. A mixed list of `pixel_rule` and `pixel_subcat` objects is not allowed.

The function receives a list of objects of class pixel_subcat and creates a list of class pixel_cat with them. However, for cases that does not need subcategories, i e that only need a set of rules,need a single set of rules, these can be passed to the function, which creates an internal subcategory object to contain them. See the examples below.

Note that it is an error to pass a mixture of pixel_rule and pixel_subcat objects.

colour can be specified in any form understood by grDevices::col2grb.

A list of class pixel_cat with the following elements:

name: a character string containing the name of the pixel category.
colour: a character string describing the colour of the pixels of the category in the classified images.
subcats: a list containing the subcategories. Their names are the names of the elements of the list.

define_rule, define_subcat, col2rgb

# The rules are not consistent, they are only useful as examples
rule01 <- define_rule("R01", "g", "b",
                      list(c(0.35, 0.30), c(0.45, 0.10)), ">=")
rule02 <- define_rule("R02", "g", "b",
                      list(c(0.35, 0.253), c(0.45, 0.253)), ">=")
rule03 <- define_rule("R03", "g", "b",
                      list(c(0.35, 0.29), c(0.49, 0.178)), ">=")
rule04 <- define_rule("R04", "g", "b",
                      list(c(0.35, 0.253), c(0.45, 0.253)), "<")

subcat01 <- define_subcat("Subcat01", rule01, rule02)
subcat02 <- define_subcat("Subcat02", rule03, rule04)

cat01 <- define_cat("Cat01", "#ffae2a", subcat01, subcat02)

# A single category defined by a set of rules, not subcategories
cat02 <- define_cat("Cat02", "#00ae2a", rule01, rule02, rule03)