add normalize argument to st_crop

[btupper]

As per #685 this pull request adds a normalize argument (default is FALSE) to the st_crop function.

Here's a demonstration of the package with the changes.

suppressPackageStartupMessages({
  library(sf)
  library(stars)
  library(dplyr)
})

## Warning: package 'sf' was built under R version 4.3.2

# read in data
filename= system.file(paste0("netcdf/", "avhrr-only-v2.19810901.nc"), package = "starsdata")
orig = read_stars(filename, sub = "sst", quiet = TRUE, proxy = FALSE)
bb = st_bbox(c(xmin = 270, ymin = 20, xmax = 300, ymax = 50), crs = st_crs(orig))
crop = st_crop(orig, bb, normalize = TRUE)
x = st_sample(bb, 10)

Compare the maximum cell index with the output of st_cells. Note the cells indices are less than the maximum possible cell index.

iorig = st_cells(orig, x)
iorig

##  [1] 330876 353902 283381 289158 294893 264667 303586 343905 276140 270388

mx = prod(dim(orig))
cat("max orig index:", mx, "\n")

## max orig index: 1036800

iorig <= mx

##  [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE

And now the same for the cropped.

icrop = st_cells(crop, x)
icrop

##  [1]  8316 10222  4381  4878  5333  2827  6106  9465  3740  3268

mx = prod(dim(crop))
cat("max cropped index:", mx, "\n")

## max cropped index: 14400

icrop <= mx

##  [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE

[edzer]

Thanks!