pixel_category: Creates a category object

Description

Creates an object of class "pixel_category", which contains a list of objects of class "pixel_subcategory".

Usage

pixel_category(cat_name, cat_colour, ...)
is.category(x)
# S3 method for pixel_category
summary(object, ...)

Value

An object of class "pixel_category" which is a list with the following elements:

name: the character string with 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 of "pixel_subcategory" objects.

Arguments

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.
...: in pixel_category() a list of objects of class "pixel_subcategory" or "pixel_rule"; in summary(), additional parameters (none needed by now).
x: the R object being tested
object: an object of class "pixel_category".

Details

The function receives a list of objects of class "pixel_subcategory" and creates an object of class "pixel_category" with them. However, subcategories are not always needed (see pixel_subcategory). In these cases "pixel_rule" objects can be passed to this function, which creates an internal subcategory object (named "S0") to contain them. See the examples below.

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

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

Examples

Run this code

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

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

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

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