readap

Read OpenDAP binary data with pure rust

Install

with cargo add:

cargo add readap

or Cargo.toml:

[dependencies]
readap = "0.1.0"

Getting Started

Read DAS metadata

let attrs = parse_das_attributes(input).unwrap();

This returns a HashMap containing all of the attributes and their children, within another hashmap

let units: String = attrs["time"]["units"].clone().try_into().unwrap();

Read a DDS dataset

let dataset = DdsDataset::from_bytes(&input).unwrap();

Read a DODS dataset

let dataset = DodsDataset::from_bytes(&input).unwrap();

Then extract the data and coordinates for a given variable

let mwd = if let DataArray::Int32(mwd) = dataset.variable_data("mean_wave_dir").unwrap() {
   	mwd
} else {
    vec![]
};

let coords = dataset.variable_coords("mean_wave_dir").unwrap();
let time_data: Vec<i32> = coords[0].1.try_into().unwrap();

Build OpenDAP query URLs

let url = dataset.query("https://example.com/data")
    .select_variable("temperature").unwrap()
    .dods_url().unwrap();

With coordinate constraints:

let url = dataset.query("https://example.com/data")
    .select_variable("temperature").unwrap()
    .select_by_coordinate("time", CoordinateConstraint::range(0, 50)).unwrap()
    .select_by_coordinate("latitude", CoordinateConstraint::single(0)).unwrap()
    .dods_url().unwrap();

For concrete examples, see the parse tests

What this library is

This library is an OpenDAP binary data and metadata parser. It is not a data downloader. It is a lower level tool to be used in higher level data access applications.

License

MIT - 2025 Matthew Iannucci