Create new vrt blocks containing derived expression bands.
Examples
if (FALSE) { # check_muparser()
s2files <- fs::dir_ls(system.file("s2-data", package = "vrtility"))
ex_collect <- vrt_collect(s2files[1])
ex_ndvi <- vrt_derived_block(
ex_collect,
ndvi ~ (B08 - B04) / (B08 + B04)
)
plot(ex_ndvi)
}