---
id: pyulog
version: "1.2.4"
license: BSD-3-Clause
license_treatment: permissive
maintenance: active
---

# pyulog — Python log parser for ULog

License: permissive · Maintenance: active · Downloads: 195.9K/mo

## What it is and what it does

pyulog is a parser and toolkit for ULog, a self-describing binary logging format used by PX4 autopilot systems. It reads ULog files and exposes their contents through both command-line scripts and a Python API. The primary use is extracting flight data from drone and robotics systems for analysis, debugging, or conversion to other formats.

The package includes six command-line tools: ulog_info displays summary statistics and message counts, ulog_messages shows logged text output, ulog_params extracts configuration parameters, ulog2csv converts data to comma-separated values, ulog2kml exports GPS tracks for map visualization, and ulog2ros2bag converts to ROS2 bag format for integration with robotics workflows. It depends only on numpy and is actively maintained.

Use it for:

- Extract flight telemetry and sensor data from PX4 autopilot logs for post-flight analysis
- Convert ULog files to CSV for data analysis in spreadsheets or statistical tools
- Export GPS trajectories from flight logs to KML for visualization in Google Earth
- Migrate ULog data to ROS2 bag format for use in robotics development pipelines
- Debug autopilot behavior by examining logged parameters and system messages
- Store and query flight logs in a database using the DatabaseULog class

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Parses ULog files (a self-describing logging format) and provides command-line tools to extract, convert, and display logged data in multiple formats including CSV, KML, and ROS2 bag files.

Yes. The package is actively maintained, has no known vulnerabilities, installs with minimal friction, and fills a specific niche for PX4/drone users who need to parse and convert ULog files. The permissive BSD license poses no restrictions. Install it if you work with PX4 logs or need ULog parsing; skip it otherwise.

## Install

pip install pyulog
uv add pyulog
poetry add pyulog

## Installing pyulog

Before you install: Low install friction with a single runtime dependency (numpy). Active maintenance with a recent release 8 days ago and steady repository activity.

License in practice: BSD-3-Clause is a permissive license allowing commercial and private use with minimal restrictions, requiring only preservation of copyright and license notices.

Quickstart:

pip install pyulog

# Command-line usage
ulog_info sample.ulg
ulog2csv sample.ulg -o output_dir

# Python API
from pyulog import ULog
log = ULog('sample.ulg')

For KML conversion, simplekml must be installed separately. For ROS2 bag conversion, a ROS2 environment with px4_msgs is required.

Verify before relying:

- Whether the package supports streaming or only full-file parsing
- Performance characteristics with large ULog files
- Completeness of the Python API documentation beyond command-line tools

## Package facts

- License: BSD-3-Clause (permissive)
- Python support: unspecified
- Install friction: low
- Maintenance: active
- Downloads: 195.9K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

ulog file parser, px4 log converter, ulog to csv, flight log analysis, ulog data extraction, ros2 bag conversion, ulog kml export, px4-autopilot, flight-data, log-parsing

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