plot_regions: Plot polygons for spectral regions

In spectrolab: Class and Methods for Spectral Data

Plot polygons for spectral regions

Description

plot_regions plots polygons for default (VIS, NIR, SWIR 1, SWIR 2) or customized regions of the spectrum.

Usage

plot_regions(
  spec,
  regions = default_spec_regions(),
  col = grDevices::rgb(0.7, 0.7, 0.7, 0.3),
  border = FALSE,
  add = TRUE,
  add_label = TRUE,
  cex_label = 1,
  ...
)

Arguments

spec	spectra object
regions	matrix with spectral regions in columns and only two rows named "begin" and "end". Values are the bands where a spectral regions begins and ends. See details for how the default regions are defined.
col	color for regions. Single value or vector of length ncol (regions).
border	color for region borders. Defaults to FALSE (no border).
add	boolean. If TRUE (default) adds polygons to current plot (if a plot exists) or throws an error if a plot does not exist. If FALSE, a new plot is created **without** any spectra.
add_label	boolean. Add region column names on top of the polygons?
cex_label	label scale
...	additional parameters passed to polygon().

Details

Default regions: spec_regions = cbind("VIS" = c(begin = 400, end = 700), "NIR" = c(begin = 800, end = 1300), "SWIR1" = c(begin = 1550, end = 1800), "SWIR2" = c(begin = 2000, end = 2400)).

Value

nothing. Called for its side effect.

Author(s)

Jose Eduardo Meireles

Examples

library(spectrolab)
spec = as_spectra(spec_matrix_example, name_idx = 1)
plot_regions(spec, default_spec_regions())
plot(spec, add = TRUE)

# Alternatively, if you want to get fancy...
col_fun = colorRampPalette(c(rgb(1, 1, 0, 0.7),rgb(1, 0, 0, 0.7)), alpha = TRUE)
colors = col_fun(4)

plot_regions(spec,default_spec_regions(), col = colors)
plot(spec, add = TRUE)

spectrolab documentation built on April 3, 2025, 9:33 p.m.