Converters

Converters are classes that are used to convert units from the raw data to standardized format. Each Converter should extend the Converter base class. The Converter base class defines one method, run, which converts a numpy ndarray of variable data from the input units to the output units.

Currently tsdat provides two converters for working with time data. StringTimeConverter converts time values in a variety of string formats, and TimestampTimeConverter converts time values in long integer format.

In addition, tsdat provides a DefaultConverter which converts any units from one UDUNITS-2 supported units type to another. This converter will be initiated if a variable’s output units (e.g “m”) are specified differently from its input units (e.g. “mm”) in the pipeline configuration file.

DefaultConverter	Default class for converting units on data arrays.
StringTimeConverter	Convert a time string to a np.datetime64, which is needed for xarray.
TimestampTimeConverter	Convert a numeric UTC timestamp to a np.datetime64, which is needed for xarray.

Converters are specified in the pipeline_config_<ingest_name>.yml file within variable definitions:

variables:
  time:
    input:
      name: time
      converter:
        classname: "tsdat.utils.converters.TimestampTimeConverter" # Converter name
        parameters:
          timezone: "US/Pacific"
          unit: "s"
    dims: [time]
    type: float
    attrs:
      long_name: Time (UTC) # automatically converts this without tz based on local computer
      standard_name: time
      units: "seconds since 1970-01-01T00:00:00"

  displacement:
    input:
      name: displacement
      units: "mm" # Units the input variable was measured in (DefaultConverter)
    dims:
      [dir, time]
    type: float
    attrs:
      units: "m" # Units the variable should be output in (DefaultConverter)
      comment: "Translational motion as measured by the buoy"