display_rgb: Plot RGB (RGBA) color composition in the PNG format.

In ursa: Non-Interactive Spatial Tools for Raster Processing and Visualization

Description

Raster images are forced to be interpeted as color composition with 3 (RGB) or 4 (RGBA) channels. Values should be in the range between 0 and 255.

Usage

display_rgb(obj, ...)

Arguments

obj	Object of class ursaRaster or list of ursaRaster objects.
...	Passed to hierarchy of plotting functions: compose_open compose_design compose_plot panel_new panel_raster panel_decor panel_graticule panel_coastline panel_scalebar compose_close

Details

If argument obj is list of ursaRaster objects (or object of class ursaStack) then obj is coerced to class ursaRaster ('stack' is coerced to 'brick').

Colorbar is not plotted.

By default, the created PNG has 24 bits per pixel. This is equal to parameter bpp=24 (compose_close). It is allow to specify other value, e.g., display_rgb(a,bpp=8).

By default, labels of gridlines are located in bottom and left sides of the panel with raster. This is equal to parameter margin=c(TRUE,TRUE,FALSE,FALSE) (panel_graticule). It is allow to specify other value, e.g., display_rgb(a,margin=T).

Currently, for color compositions the argument useRaster (panel_raster) is introduced to fix possible coordinate mismatch for Cairo-devices, but have never used.

Value

Function returns NULL value.

Author(s)

Nikita Platonov [e-mail]

See Also

display, display_brick, display_stack

Examples

session_grid(NULL)
a <- ursa_dummy(nband=3)
display_rgb(a)

ursa documentation built on Feb. 26, 2020, 3:01 p.m.