Plot an image index

Usage

plot_index(
  img = NULL,
  object = NULL,
  index = NULL,
  remove_bg = TRUE,
  viewer = get_pliman_viewer(),
  all_layers = TRUE,
  layer = 1,
  max_pixels = 5e+05,
  downsample = NULL,
  downsample_fun = NULL,
  color_regions = custom_palette(),
  ncol = NULL,
  nrow = NULL,
  aspect_ratio = NA
)

Arguments

img: An optional Image object or an object computed with image_index(). If object is provided, then the input image is obtained internally.
object: An object computed with analyze_objects_shp(). By using this object you can ignore img.
index: The index to plot. Defaults to the index computed from the object if provided. Otherwise, the B index is computed. See image_index() for more details.
remove_bg: Logical value indicating whether to remove the background when object is provided. Defaults to TRUE.
viewer: The viewer option. If not provided, the value is retrieved using get_pliman_viewer(). This option controls the type of viewer to use for interactive plotting. The available options are "base" and "mapview". If set to "base", the base R graphics system is used for interactive plotting. If set to "mapview", the mapview package is used. To set this argument globally for all functions in the package, you can use the set_pliman_viewer() function. For example, you can run set_pliman_viewer("mapview") to set the viewer option to "mapview" for all functions.
all_layers: Render all layers when img is an object computed with image_index() and viewer = "mapview"?.
layer: The layer to plot when img is an object computed with image_index() and viewer = "mapview". Defaults to the first layer (first index computed).
max_pixels: integer > 0. Maximum number of cells to plot the index. If max_pixels < npixels(img), downsampling is performed before plotting the index. Using a large number of pixels may slow down the plotting time.
downsample: integer; for each dimension the number of pixels/lines/bands etc that will be skipped; Defaults to NULL, which will find the best downsampling factor to approximate the max_pixels value.
downsample_fun: function; if given, downsampling will apply downsample_fun`` to each of the the subtiles.
color_regions: The color palette for displaying index values. Default is custom_palette().
nrow, ncol: The number of rows or columns in the plot grid. Defaults to NULL, i.e., a square grid is produced.
aspect_ratio: Numeric, giving the aspect ratio y/x. Defaults to NA. See graphics::plot.window() for more details.

Value

None

Examples

if(interactive()){
# Example usage:
library(pliman)
img <- image_pliman("sev_leaf.jpg")
plot_index(img, index = "B")
}