arlmet.Header

class arlmet.Header(year, month, day, hour, forecast, level, grid, variable, exponent, precision, initial_value)

Fixed-width 50-byte header present at the start of every ARL record.

Headers are immutable value objects; use dataclasses.replace() to derive a modified copy.

Parameters:

• year (int) – Valid time components stored in the record header.

• month (int) – Valid time components stored in the record header.

• day (int) – Valid time components stored in the record header.

• hour (int) – Valid time components stored in the record header.

• forecast (int) – Forecast hour associated with the record.

• level (int) – ARL vertical level index.

• grid (tuple[int, int]) – Thousands part of the x and y grid sizes, as stored in the header’s two grid letters ((1000, 0) for a 1799x799 grid; (0, 0) below 1000 points). The remainders live in the index record, whose nx/ny are the full sizes.

• variable (str) – Four-character ARL variable name.

• exponent (int) – Differential packing exponent.

• precision (float) – Packed-data precision used during unpacking.

• initial_value (float) – Initial grid value at the start of the differential packing stream.

N_BYTES

Fixed serialized size of the header.

Type:

int

time

Timestamp reconstructed from the header date fields.

Type:

pandas.Timestamp

from_bytes(data)

Parse a Header from raw bytes.

tobytes()

Serialize the header to its fixed-width ASCII representation.

Methods

Header.__init__(year, month, day, hour, ...)
Header.from_bytes(data)	Parse header from raw bytes.
Header.tobytes()	Serialize the header to its fixed-width ASCII representation.

Attributes

Header.FIELDS
Header.N_BYTES
Header.time	Timestamp reconstructed from the header date fields.
Header.year
Header.month
Header.day
Header.hour
Header.forecast
Header.level
Header.grid
Header.variable
Header.exponent
Header.precision
Header.initial_value