This is a web application for flight log analysis. It allows users to upload ULog flight logs, and analyze them through the browser.

It uses the bokeh library for plotting and the Tornado Web Server.

• clone the repository
• use python3
• pip3 install bokeh jinja2 pyulog pandas simplekml (at least version 0.12.5 of bokeh is required)
• sudo apt-get install sqlite3
• configure web server config (this can be skipped for a local installation): create a file config_user.ini and copy and adjust the sections and values from config_default.ini that should be overridden.
• ./setup_db.py to initialize the database

For local usage, the server can be started directly with a log file name, without having to upload it first:

./serve.py -f <file.ulg>

The plot_app directory contains a bokeh server application for plotting. It can be run stand-alone with bokeh serve --show plot_app (or with cd plot_app; bokeh serve --show main.py, to start without the html template).

The whole web application is run with the serve.py script. Run ./serve.py -h for further details.

The plotting can also be used interative using a Jupyter Notebook. It requires python knowledge, but provides full control over what and how to plot with immediate feedback.

• pip3 install jupyter
• Start the notebook: jupyter notebook
• open the testing_notebook.ipynb file

• Google Maps seems to have some problems (initialization, scaling and zooming issues). This is bokeh
• maximum upload size is currently limited to 100MB. This requires a bokeh setting.
• add SSL
• Not all bokeh widgets seem to be responsive to size changes
• better downsampling (use JS callback with queue & timeout (like InteractiveImage) and better algorithm)
• add location obfuscation option
• user management: login, per-user display templates
• download CSV option?
• ...

Reading ULog files is expensive and thus should be avoided if not really necessary. There are two mechanisms helping with that:

• Loaded ULog files are kept in RAM using an LRU cache with configurable size (when using the helper method). This works from different requests and sessions and from all source contexts.
• There's a LogsGenerated DB table, which contains extracted data from ULog for faster access.

Tornado uses a single-threaded event loop. This means all operations should be non-blocking (see also http://www.tornadoweb.org/en/stable/guide/async.html).

Bokeh uses dynamic code loading and the plot_app/main.py gets loaded on each session (page load) to isolate requests. This also means we cannot use relative imports. We have to use sys.path.append to include modules in plot_app from the root directory (Eg tornado_handlers.py). Then to make sure the same module is only loaded once, we use import xy instead of import plot_app.xy. It's useful to look at print('\n'.join(sys.modules.keys())) to check this.

Contributions are welcome! Just open a pull request with detailed description why the changes are needed, or open an issue for bugs, feature requests, etc...