Working with Gridded Data

The hf_hydrodata module provides functionality to get gridded data and metadata from the HydroData data catalog. This is a list of the most useful functions for working with gridded data. See the Python API Refererence for details about each function.

Gridded Observation Methods

• get_gridded_data
• get_gridded_files
• get_raw_file
• get_date_range
• get_catalog_entry
• get_catalog_enties
• get_citations
• get_datasets
• get_variables
• from_latlon
• to_latlon
• get_huc_from_xy
• get_huc_from_latlon
• get_huc_bbox

Filter Parameters

Most gridded functions accept filter parameters that identify data using attributes that index the data. These filter parameters may be passed by name or using a python dict with filter parameters options. All the files are organized by dataset and variable (see Datasets).

You can get the available datasets and variables using functions:

import hf_hydrodata as hf

datasets = hf.get_datasets()
variables = hf.get_variables()

You can pass filter parameter using named parameters.

datasets = hf.get_datasets(variable = "air_temp")

You use pass filter parameters as dict options as well.

options = {"dataset": "NLDAS2", "grid": "conus1"}
variables = hf.get_variables(options)

See the Python API Refererence or Datasets for a list of all the filter parameters that may be provided.

Metadata Descriptions

You can get metadata about the files in hydrodata using the get_catalog_entry function.

import hf_hydrodata as hf

options = {
   "dataset": "NLDAS2", "variable": "precipitation", "period": "hourly",
   "start_time": "2005-10-1", "end_time": "2005-11-1"
}
metadata = hf.get_catalog_entry(options)
print(metadata["units"], metadata["paper_dois"], metadata["grid"], metadata["description"])

See Metadata for documentation of the metadata returned by get_catalog_entry.

You can get the date range available for a data set using the get_date_range function.

(start_date, end_date) = hf.get_date_range(options)