functions to interact with gdal not meant to be called directly by users (but e.g. by stars::read_stars)

Usage

gdal_read(
  x,
  ...,
  options = character(0),
  driver = character(0),
  read_data = TRUE,
  NA_value = NA_real_,
  RasterIO_parameters = list()
)

gdal_write(
  x,
  ...,
  file,
  driver = "GTiff",
  options = character(0),
  type = "Float32",
  NA_value = NA_real_,
  geotransform,
  update = FALSE,
  scale_offset = c(1, 0)
)

gdal_inv_geotransform(gt)

gdal_crs(file, options = character(0))

gdal_metadata(
  file,
  domain_item = character(0),
  options = character(0),
  parse = TRUE
)

gdal_subdatasets(file, options = character(0), name = TRUE)

gdal_polygonize(
  x,
  mask = NULL,
  file = tempfile(),
  driver = "GTiff",
  use_integer = TRUE,
  geotransform,
  breaks = classInt::classIntervals(na.omit(as.vector(x[[1]])))$brks,
  use_contours = FALSE,
  contour_lines = FALSE,
  connect8 = FALSE,
  ...
)

gdal_rasterize(sf, x, gt, file, driver = "GTiff", options = character())

gdal_extract(
  f,
  pts,
  resampling = c("nearest", "bilinear", "cubic", "cubicspline")
)

gdal_read_mdim(
  file,
  array_name = character(0),
  options = character(0),
  offset = integer(0),
  count = integer(0),
  step = integer(0),
  proxy = FALSE,
  debug = FALSE
)

gdal_write_mdim(
  file,
  driver,
  dimx,
  cdl,
  wkt,
  xy,
  ...,
  root_group_options = character(0),
  options = character(0),
  as_float = TRUE
)

gdal_create(f, nxy, values, crs, xlim, ylim)

Arguments

x: character vector, possibly of length larger than 1 when more than one raster is read
...: ignored
options: character; driver specific options regarding reading or creating the dataset
driver: character; driver short name; when empty vector, driver is auto-detected.
read_data: logical; if FALSE, only the imagery metadata is returned
NA_value: (double) non-NA value to use for missing values; if NA, when writing missing values are not specially flagged in output dataset, when reading the default (dataset) missing values are used (if present / set).
RasterIO_parameters: list with named parameters to GDAL's RasterIO; see the stars::read_stars documentation.
file: file name
type: gdal write type
geotransform: length 6 numeric vector with GDAL geotransform parameters.
update: logical; TRUE if in an existing raster file pixel values shall be updated.
scale_offset: length 2 numeric; contains scale and offset values
gt: double vector of length 6
domain_item: character vector of length 0, 1 (with domain), or 2 (with domain and item); use "" for the default domain, use NA_character_ to query the domain names.
parse: logical; should metadata be parsed into a named list (TRUE) or returned as character data?
name: logical; retrieve name of subdataset? If FALSE, retrieve description
mask: stars object with NA mask (0 where NA), or NULL
use_integer: boolean; if TRUE, raster values are read as (and rounded to) unsigned 32-bit integers values; if FALSE they are read as 32-bit floating points numbers. The former is supposedly faster.
breaks: numeric vector with break values for contour polygons (or lines)
use_contours: logical;
contour_lines: logical;
connect8: logical; if TRUE use 8 connection algorithm, rather than 4
sf: object of class sf
f: character; file name
pts: points matrix
resampling: character; resampling method; for method cubic or cubicspline, stars_proxy objects should be used and GDAL should have version >= 3.10.0
array_name: array name
offset: offset (pixels)
count: number of pixels to read
step: step size (pixels)
proxy: logical; return proxy object?
debug: logical; print debug messages?
dimx: integer named vector with dimensions of object
cdl: list with variables, each having a named dim attribute
wkt: character; WKT of crs
xy: character; names of the spatial x and y dimension
root_group_options: character; driver specific options regarding the creation of the root group
as_float: logical; when TRUE write 4-byte floating point numbers, when FALSE write 8-byte doubles.
nxy: integer vector of length 2
values: fill value
crs: object of class crs
xlim: numeric
ylim: numeric

Value

object of class crs, see st_crs.

named list with metadata items

gdal_subdatasets returns a zero-length list if file does not have subdatasets, and else a named list with subdatasets.

Details

These functions are exported for the single purpose of being used by package stars, they are not meant to be used directly and may change or disappear without prior notice or deprecation warnings.

gdal_inv_geotransform returns the inverse geotransform

gdal_crs reads coordinate reference system from GDAL data set

get_metadata gets metadata of a raster layer

gdal_subdatasets returns the subdatasets of a gdal dataset

Examples

if (FALSE) { # \dontrun{
  f = system.file("tif/L7_ETMs.tif", package="stars")
  f = system.file("nc/avhrr-only-v2.19810901.nc", package = "stars")
  gdal_metadata(f)
  gdal_metadata(f, NA_character_)
  try(gdal_metadata(f, "wrongDomain"))
  gdal_metadata(f, c("", "AREA_OR_POINT"))
} # }