reduce dimension to rgb (alpha) hex values

st_rgb(
  x,
  dimension = 3,
  use_alpha = dim(x)[dimension] == 4,
  maxColorValue = 255L,
  probs = c(0, 1),
  stretch = FALSE
)

Arguments

x

object of class stars

dimension

dimension name or number to reduce

use_alpha

logical; if TRUE, the fourth band will be used as alpha values

maxColorValue

integer; maximum value for colors

probs

probability values for quantiles used for stretching

stretch

logical; if TRUE, each band is stretched to 0 ... maxColorValue

Details

the dimension's bands are mapped to red, green, blue, alpha; if a different ordering is wanted, use [.stars to reorder a dimension, see examples

See also

Examples

tif = system.file("tif/L7_ETMs.tif", package = "stars") x = read_stars(tif) st_rgb(x[,,,3:1])
#> stars object with 2 dimensions and 1 attribute #> attribute(s): #> L7_ETMs.tif #> Length:122848 #> Class :character #> Mode :character #> dimension(s): #> from to offset delta refsys point values x/y #> x 1 349 288776 28.5 UTM Zone 25, Southern Hem... FALSE NULL [x] #> y 1 352 9120761 -28.5 UTM Zone 25, Southern Hem... FALSE NULL [y]
r = st_rgb(x[,,,c(6,5,4,3)], 3, use_alpha=TRUE) # now R=6,G=5,B=4,alpha=3 if (require(ggplot2)) { ggplot() + geom_stars(data = r) + scale_fill_identity() }