dimensions `point` attribute changed by writing to disk

[btupper]

Hi,

When writing and then reading a regular grid to/from disk, the dimensions point attribute changes from NA to FALSE. The two (original and from-disk) versions cannot be concatenated then because, of course, the dimensional attributes don't match.

I assume that I could get/modify/set the dimension attributes so that they match, but I am hopeful that there exists a cleaner way to manage that by controlling read_stars or write_stars. Perhaps there magic gdal arguments? I have looked at gdal's geotiff specifications, but nothing jumps out at me.

Below is a small example.

Thanks so much!
Ben

ofile = tempfile(fileext = ".tif")

a = stars::read_stars(system.file("nc/reduced.nc", package = "stars")) |> 
  dplyr::slice("time",1) |>
  dplyr::select("sst") |>
  sf::st_set_crs(4326) |>
  stars::write_stars(ofile)
#> sst, anom, err, ice,

b = stars::read_stars(ofile)

da = stars::st_dimensions(a)
db = stars::st_dimensions(b)
cat("point in a:", da$x$point, "\n")
#> point in a: NA
cat("point in b:", db$x$point, "\n")
#> point in b: FALSE

c = c(a, b, along = NA_integer_)
#> Error in c.stars(a, b, along = NA_integer_): don't know how to merge arrays: please specify parameter along

sessionInfo()
#> R version 4.4.2 (2024-10-31)
#> Platform: x86_64-apple-darwin20
#> Running under: macOS Sequoia 15.3.2
#> 
#> Matrix products: default
#> BLAS:   /Library/Frameworks/R.framework/Versions/4.4-x86_64/Resources/lib/libRblas.0.dylib 
#> LAPACK: /Library/Frameworks/R.framework/Versions/4.4-x86_64/Resources/lib/libRlapack.dylib;  LAPACK version 3.12.0
#> 
#> locale:
#> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
#> 
#> time zone: America/New_York
#> tzcode source: internal
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> loaded via a namespace (and not attached):
#>  [1] vctrs_0.6.5        cli_3.6.4          knitr_1.48         rlang_1.1.5       
#>  [5] xfun_0.48          DBI_1.2.3          KernSmooth_2.23-24 generics_0.1.3    
#>  [9] sf_1.0-19          glue_1.8.0         htmltools_0.5.8.1  e1071_1.7-16      
#> [13] rmarkdown_2.28     grid_4.4.2         tibble_3.2.1       evaluate_1.0.0    
#> [17] classInt_0.4-11    abind_1.4-8        fastmap_1.2.0      yaml_2.3.10       
#> [21] lifecycle_1.0.4    compiler_4.4.2     dplyr_1.1.4        fs_1.6.4          
#> [25] pkgconfig_2.0.3    Rcpp_1.0.14        rstudioapi_0.17.0  digest_0.6.37     
#> [29] R6_2.6.1           tidyselect_1.2.1   class_7.3-22       reprex_2.1.1      
#> [33] pillar_1.10.1      parallel_4.4.2     magrittr_2.0.3     tools_4.4.2       
#> [37] withr_3.0.2        proxy_0.4-27       stars_0.6-8        units_0.8-5

^{Created on 2025-04-07 with reprex v2.1.1}