
R Under development (unstable) (2026-07-18 r90277 ucrt) -- "Unsuffered Consequences"
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Platform: x86_64-w64-mingw32/x64

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> suppressPackageStartupMessages(library(stars))
> 
> s5p = system.file("sentinel5p/S5P_NRTI_L2__NO2____20180717T120113_20180717T120613_03932_01_010002_20180717T125231.nc", package = "starsdata")
> if (s5p != "") {
+ 
+ lat_ds = paste0("HDF5:\"", s5p, "\"://PRODUCT/latitude")
+ lon_ds = paste0("HDF5:\"", s5p, "\"://PRODUCT/longitude")
+ nit_ds = paste0("HDF5:\"", s5p, "\"://PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/nitrogendioxide_summed_total_column")
+ lat = read_stars(lat_ds)
+ lon = read_stars(lon_ds)
+ nit = read_stars(nit_ds)
+ nit[[1]][nit[[1]] > 9e+36] = NA
+ 
+ ll = setNames(c(lon, lat), c("x", "y"))
+ nit.c0 = st_as_stars(nit, curvilinear = ll)
+ 
+ # more direct method:
+ nit.c = read_stars(s5p, sub = "//PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/nitrogendioxide_summed_total_column",
+ 	curvilinear = c("//PRODUCT/longitude", "//PRODUCT/latitude"), driver = NULL)
+ if (inherits(nit.c[[1]], "units"))
+ 	nit.c[[1]] = units::drop_units(nit.c[[1]])
+ nit.c[[1]][nit.c[[1]] > 9e+36] = NA
+ all.equal(nit.c0, nit.c)
+ st_crs(nit.c) = 4326
+ print(nit.c)
+ 
+ if (FALSE && capabilities()["png"]) {
+  png("nit1.png", 800, 800)
+  plot(nit.c, breaks = "equal", reset = FALSE, axes = TRUE, as_points = TRUE, pch = 16)
+  maps::map('world', add = TRUE, col = 'red')
+  dev.off()
+ 
+  png("nit2.png", 800, 800)
+  plot(nit.c, breaks = "equal", reset = FALSE, axes = TRUE, as_points = FALSE, border = NA)
+  maps::map('world', add = TRUE, col = 'red')
+  dev.off()
+ 
+  nit.c = stars:::st_downsample(nit.c, 8)
+  print(nit.c)
+  
+  png("nit3.png", 800, 800)
+  plot(nit.c, breaks = "equal", reset = FALSE, axes = TRUE, as_points = TRUE, pch = 16)
+  maps::map('world', add = TRUE, col = 'red')
+  dev.off()
+ 
+  png("nit4.png", 800, 800)
+  plot(nit.c, breaks = "equal", reset = FALSE, axes = TRUE, as_points = FALSE, border = NA)
+  maps::map('world', add = TRUE, col = 'red')
+  dev.off()
+ }
+ 
+ }
> 
> proc.time()
   user  system elapsed 
   0.64    0.09    0.67 
