fewsxml 0.2.0

A library for reading and writing XML files to interact with Delft-FEWS.

fewsxml

Table of Contents

• Installation
• Overview
• Usage Example
  • Creating a PI-XML File and Writing to Disk
  • Reading a PI-XML File and Creating Pydantic Models
• API Reference
• Schema Compatibility

Installation

pip install fewsxml

Overview

fewsxml provides Python APIs to construct, read, and write PI-XML files compatible with the Delft-FEWS system. It uses Pydantic models for data validation and supports the PI TimeSeries schema.

There are two main categories of functions:

1. Creating PI-XML Files: Functions to create PIHeader, PISeries, and PITimeSeries objects, and to write them to XML files.
2. Reading PI-XML Files: Functions to read and parse existing PI-XML files into Pydantic models.

Usage Example

Creating a PI-XML File and Writing to Disk

Below is a minimal example to create a PI-XML file with a time series, including all required header fields such as timeStep and missVal:

from fewsxml import (
    create_pi_header, create_pi_series, create_pi_timeseries, write,
    PITimeStep
)
from datetime import datetime

time_step = PITimeStep(unit="second", multiplier=3600)

# Create the header with all required fields
header = create_pi_header(
    type="instantaneous",
    location_id="LOC001",
    parameter_id="H.waterlevel",
    start_date=datetime(2023, 1, 1, 0, 0),
    end_date=datetime(2023, 1, 1, 2, 0),
    timeStep=time_step,
    missVal="-999"
)

# Create events (time series values)
events = [
    {"date": datetime(2023, 1, 1, 0, 0), "value": 1.23},
    {"date": datetime(2023, 1, 1, 1, 0), "value": 1.25},
    {"date": datetime(2023, 1, 1, 2, 0), "value": 1.20},
]

# Build the series and root object
series = create_pi_series(header, events)
pi = create_pi_timeseries(series)

# Write to XML file
write(pi, "output.xml")

Reading a PI-XML File and Creating Pydantic Models

import fewsxml as fx
parsed_timeseries = fx.read("timeseries_import.xml")

The parsed_timeseries variable now contains a PITimeSeries object with all data from the XML file, accessible via Pydantic models. As mentioned in the previous example, you can create an XML file from these models using the write function: fx.write(parsed_timeseries, "output.xml"). The created XML file will be compatible with the PI TimeSeries schema.

API Reference

• create_pi_header(...): Creates a PIHeader object (series metadata).
• create_pi_series(header, events, ...): Creates a PISeries object from a header and events.
• create_pi_timeseries(series, ...): Creates the root PITimeSeries object.
• write(pi, filename): Writes a PITimeSeries object to an XML file.

Schema Compatibility

The generated XML files are compatible with the PI TimeSeries schema.