osobhandClaude Opus 5.5
31efac1ae1
Dimension::size of an unlimited dimension was its dimension scale's extent, which netCDF-C leaves at 0, so it read 0 for a dimension holding records. It is now what netCDF-C reports (nc4_find_dim_len): the largest current extent of the variables using it in any group, found through the scale's REFERENCE_LIST, a coordinate variable's own extent included; 0 when nothing has been written. interop_tests::unlimited_dimension_lengths_match_netcdf4_python compares with netCDF4-python (variables of different lengths, one in a subgroup, an unwritten dimension, a coordinate variable shorter than another variable on its dimension, a subgroup's own dimension); before the fix it got time 0/6, rec 3/5, srec 0/1. The known-issues entry moves to Fixed; the crate README's warning goes. A new open entry records a related bug found meanwhile: variables' dimensions are matched by size, not DIMENSION_LIST. Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
2.3 KiB
2.3 KiB
clawhdf5-netcdf4
Read NetCDF-4 files in pure Rust. NetCDF-4 files are HDF5 files with
conventions for dimensions, coordinate variables and attributes; this crate
reads them through the clawhdf5 facade, with no
libnetcdf or libhdf5. Read-only: NetCDF-3 (classic) files are not HDF5 and
are not supported.
Not on crates.io yet; depend on it from git:
[dependencies]
clawhdf5-netcdf4 = { git = "https://git.redclaw.dev/quantumclaw/clawhdf5" }
Usage
use clawhdf5_netcdf4::NetCDF4File;
let nc = NetCDF4File::open("climate.nc")?;
for dim in nc.dimensions()? {
println!("{}: {} (unlimited = {})", dim.name, dim.size, dim.is_unlimited);
}
let mut temp = nc.variable("temperature")?;
let dims: Vec<&str> = temp.dimensions().iter().map(|d| d.name.as_str()).collect();
println!("{:?} over {:?}", temp.shape()?, dims);
let cf = temp.cf_attributes()?;
println!("units: {:?}", cf.units);
// scale_factor/add_offset applied; _FillValue and missing_value become NaN
let values: Vec<f64> = temp.read_f64()?;
# Ok::<(), clawhdf5_netcdf4::Error>(())
API
| Item | What |
|---|---|
NetCDF4File |
open, from_bytes, dimensions, variables, variable, global_attrs, group, group_names, nc_properties, and hdf5_file for the underlying clawhdf5::File |
NetCDF4Group |
the same for a sub-group (dimensions, variables, attrs, nested group) |
Variable |
name, shape, dimensions, nc_type, is_coordinate, attrs, cf_attributes; read_f64 (CF scale/offset and fill applied), read_raw_f32/_f64/_i32/_i64/_u64, read_string, read_raw |
Dimension |
name, size, is_unlimited (an unlimited dimension's size is its current length as netCDF-C reports it: the largest extent of the variables using it) |
CfAttributes |
CF convention attributes: units, long_name, standard_name, fill_value (_FillValue), missing_value, scale_factor, add_offset, valid_range, calendar, axis |
NcType |
the NetCDF type of a variable |
No cargo features. Tests compare against files written by netCDF4-python
(tests/interop_tests.rs; the CI job requires them with
CLAWHDF5_REQUIRE_INTEROP=1). What the HDF5 reader underneath cannot
read is listed in docs/known-issues.md.
License
MIT