mdim function

Read or write data using GDAL's multidimensional array API

read_mdim(
  filename,
  variable = character(0),
  ...,
  options = character(0),
  raster = NULL,
  offset = integer(0),
  count = integer(0),
  step = integer(0),
  proxy = FALSE,
  debug = FALSE,
  bounds = TRUE,
  curvilinear = NA
)

write_mdim(
  x,
  filename,
  driver = detect.driver(filename),
  ...,
  root_group_options = character(0),
  options = character(0),
  as_float = TRUE
)

Arguments

• filename: name of the source or destination file or data source
• variable: name of the array to be read; if "?", a list of array names is returned, with group name as list element names.
• ...: ignored
• options: character; driver specific options regarding the opening (read_mdim) or creation (write_mdim) of the dataset
• raster: names of the raster variables (default: first two dimensions)
• offset: integer; zero-based offset for each dimension (pixels) of sub-array to read, defaults to 0 for each dimension(requires sf >= 1.0-9)
• count: integer; size for each dimension (pixels) of sub-array to read (default: read all); a value of NA will read the corresponding dimension entirely; counts are relative to the step size (requires sf >= 1.0-9)
• step: integer; step size for each dimension (pixels) of sub-array to read; defaults to 1 for each dimension (requires sf >= 1.0-9)
• proxy: logical; return proxy object?
• debug: logical; print debug info?
• bounds: logical or character: if TRUE tries to infer from "bounds" attribute; if character, named vector of the form c(longitude="lon_bnds", latitude="lat_bnds") with names dimension names
• curvilinear: control reading curvilinear (geolocation) coordinate arrays; if NA try reading the x/y dimension names; if character, defines the arrays to read; if FALSE do not try; see also read_stars
• x: stars object
• driver: character; driver name
• root_group_options: character; driver specific options regarding the creation of the root group
• as_float: logical; if TRUE write 4-byte floating point numbers, if FALSE write 8-byte doubles

Details

it is assumed that the first two dimensions are easting and northing

Examples

set.seed(135)
m = matrix(runif(10), 2, 5)
names(dim(m)) = c("stations", "time")
times = as.Date("2022-05-01") + 1:5
pts = st_as_sfc(c("POINT(0 1)", "POINT(3 5)"))
s = st_as_stars(list(Precipitation = m)) |>
 st_set_dimensions(1, values = pts) |>
 st_set_dimensions(2, values = times)
nc = tempfile(fileext=".nc")
if (compareVersion(sf_extSoftVersion()["GDAL"], "3.4.0") > -1) {
  write_mdim(s, nc)
  # try ncdump on the generated file
  print(read_mdim(nc))
}

See Also

gdal_utils , in particular util mdiminfo to query properties of a file or data source containing arrays