image_view {pliman}

Create an interactive map view of an image

Description

This function allows users to interactively edit and analyze an image using mapview and mapedit packages.

Usage

image_view(
  img,
  object = NULL,
  r = 1,
  g = 2,
  b = 3,
  alpha = 0.7,
  attribute = "area",
  title = "Edit the image",
  show = c("rgb", "index"),
  index = "B",
  max_pixels = 1e+06,
  downsample = NULL,
  color_regions = custom_palette(),
  quantiles = c(0, 1),
  domain = NULL,
  ...
)

Arguments

img

An Image object.

object

(Optional). An object computed with analyze_objects(). If an object is informed, an additional layer is added to the plot, showing the contour of the analyzed objects, with a color gradient defined by attribute.

r, g, b

The layer for the Red, Green and Blue band, respectively. Defaults to 1, 2, and 3.

alpha

The transparency level of the rectangles' color (between 0 and 1).

attribute

The name of the quantitative variable in the object_index to be used for coloring the rectangles.

title

The title of the map view. Use to provide short orientations to the user.

show

The display option for the map view. Options are "rgb" for RGB view and "index" for index view.

index

The index to use for the index view. Defaults to "B".

max_pixels

integer > 0. Maximum number of cells to use for the plot. If max_pixels < npixels(img), regular sampling is used before plotting.

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.

color_regions

The color palette for displaying index values. Default is custom_palette().

quantiles

the upper and lower quantiles used for color stretching. If set to NULL, stretching is performed basing on 'domain' argument.

domain

the upper and lower values used for color stretching. This is used only if 'quantiles' is NULL. If both '⁠domain'⁠ and 'quantiles' are set to NULL, stretching is applied based on min-max values.

...

Additional arguments to be passed to downsample_fun.

Value

An sf object, the same object returned by mapedit::editMap().

Examples

if(interactive()){
# Example usage:
img <- image_pliman("sev_leaf.jpg")
image_view(img)
}