> For the complete documentation index, see [llms.txt](https://yagsl.yassrobotics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yagsl.yassrobotics.com/how-to-guides/view-your-datalog-in-advantagescope.md). # View your DataLog in AdvantageScope {% hint style="danger" %} **This is not "Log Replay."** [AdvantageKit's Log Replay](https://docs.advantagekit.org/getting-started/what-is-advantagekit) re-runs your robot code against a recorded log to deterministically reproduce a match in simulation, and requires the AdvantageKit IO-interface pattern. What this page covers is simpler and works with **every** YAGSL robot, AdvantageKit or not: opening the `.wpilog` file your robot already wrote and looking at the recorded values in AdvantageScope. Nothing re-executes — you're just viewing a file. {% endhint %} Every field `SwerveParser` publishes to NetworkTables is also written to a WPILib `DataLog` automatically — no JSON field or code needed to opt in. See [Telemetry, Simulation & Vision](/explanation/telemetry-and-vision.md) for the live NetworkTables tree; this page is the practical walkthrough for looking at a *recorded* run afterward. ## Step 1: Make sure a DataLog is actually being written `DataLogManager` owns the actual file on disk. Start it once, early, in `Robot.java`: ```java @Override public void robotInit() { DataLogManager.start(); DriverStation.startDataLog(DataLogManager.getLog()); // optional: also logs joystick/DS data } ``` {% hint style="info" %} If you never call `DataLogManager.start()` yourself, it still starts lazily the first time `SwerveParser` publishes a field — but calling it explicitly in `robotInit()` guarantees the log begins at power-on (not at the first telemetry update) and lets you fold in DS/joystick data with `DriverStation.startDataLog(...)`. {% endhint %} On the real robot, `.wpilog` files are written to a USB drive if one is plugged in, otherwise to `/home/lvuser/logs` on the roboRIO's internal storage. In simulation, they land in your project's `logs/` folder next to `build.gradle`. WPILib initially names the file `FRC_TBD_.wpilog` and renames it to a timestamp (e.g. `FRC_20260817_010558.wpilog`) once it has a real time source. ## Step 2: Nothing to configure — YAGSL logs automatically Unlike hand-building a `SwerveDriveConfig`/`SwerveModuleConfig` yourself, `SwerveParser` already wires up a `DataLog` name for the drive and every module, at every level, for you: * `Swerve` — the drive itself (pose, gyro, chassis speeds, module states). * `Swerve/modules/` — that module's absolute encoder. * `Swerve/modules//drive` — that module's drive motor. * `Swerve/modules//azimuth` — that module's angle/steering motor. {% hint style="warning" %} Note the DataLog tree uses a top-level `Swerve` (capitalized, no `Mechanisms` prefix) — a *different* root than the live NetworkTables tree covered in [Telemetry, Simulation & Vision](/explanation/telemetry-and-vision.md) (`Mechanisms/swerve`, lowercase). Both describe the same data; AdvantageScope shows them as two separate branches in the field tree (`Swerve` for the DataLog-only entries, `NT` for the live/mirrored NetworkTables ones) — see the sidebar in the screenshots below. {% endhint %} There's no granular per-field opt-in and no way to disable this — if you're using `SwerveParser`, you already have a full DataLog recording of your swerve drive every time you run the robot. ## Step 3: Run it and record Deploy or simulate the robot, enable it, and drive around for a bit — every field above writes to both NetworkTables and the DataLog continuously while enabled. ## Step 4: Pull the file and open it in AdvantageScope 1. Grab the `.wpilog` off the RIO (USB drive, or `scp lvuser@10.TE.AM.2:/home/lvuser/logs/*.wpilog .`) — or straight from your sim project's `logs/` folder. 2. Open **AdvantageScope**, then **File → Open File...** (or drag the `.wpilog` onto the window). Do **not** use "Connect to Robot/Simulator" — that connects live over NetworkTables, which shows *current* values, not the recorded run. ## Step 5: Explore the data Add a tab to visualize the data: * **2D Field** tab — drag `Swerve/pose` in to see the robot's recorded path.

Scrubbing a recorded run's path on the 2D Field tab, fed from Swerve/pose.

* **Swerve** tab — AdvantageScope's built-in module visualizer. Drag `Swerve/states/current` (and optionally `Swerve/states/desired` and `Swerve/chassis/current`/`desired`) into the **Sources** list to see wheel vectors animate over the timeline.

The Swerve tab replaying recorded module states — translating, then spinning in place.

* **Line Graph** tab — drag any numeric field to plot it over time. A useful pairing while debugging: each module's `Swerve/modules//azimuth/mechanism/position` (the angle motor's own relative encoder, from the DataLog) against `Mechanisms/swerve/modules//encoder` (the raw absolute encoder, from the live NT mirror also present in the file) — if the two drift apart over a run, the relative encoder seeded from the wrong absolute offset.

Dragging each module's azimuth position and absolute encoder fields into the Line Graph tab.

Scrub the timeline at the top of the window to step through the run, or hit play to watch it back at normal speed. {% hint style="success" %} Because this is just a file, you can open the same `.wpilog` in as many tabs/windows as you want, compare two different matches side by side, or hand the file to a teammate to look at independently — none of that requires the robot, the simulator, or AdvantageKit replay to be running. {% endhint %} ## Related pages * [Telemetry, Simulation & Vision](/explanation/telemetry-and-vision.md) * [How to set up AdvantageScope](/how-to-guides/set-up-advantagescope.md) * [Schema Changes](/reference/schema-changes.md) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://yagsl.yassrobotics.com/how-to-guides/view-your-datalog-in-advantagescope.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.