Lap Analyser Help

This is a little tool for motorsports enthusiasts. It allows you to gain insight into your laps from nothing more than action camera (such as GoPro) video footage.

It can currently show you lap times, total, longitudinal acceleration. For laps using cars lateral acceleration is shown, for motorcycles the lean angle is estimated.

Please note that this tool is still at a very early stage. It does contain bugs and lacks a lot of useful features. This also means that your feedback would be highly appreciated.

Getting started

To use the lap analyser you need to load either a video recorded with a GoPro action camera or a NMEA GPS recording.

• Click on Add Lap
• Select whether you were on a bike or car under Vehicle Dynamics
• Select the files to be loaded using Choose Files.
• The file will not be uploaded but processing can take a while (up to several minutes, depending on the speed of your computer).
• Enter the name of the track under name
• The start finish line will automatically be chosen on a straight but can also be set manually either from the video or by using the coordinatess.
• If you enter the latitude and longitude manually they need to be in decimal notation.
• The heading is the direction of travel when crossing the finish line (so it should be prependicular to the actual line on the ground).
• Click Open Session
• You can now find the laps in the sidebar on the left or under the menu ().

Supported Files:

• GoPro videos recorded with GPS enabled (.MP4, .LRV)
• NMEA GPS Recordings (.NMEA, .TXT)

Note that NMEA recordings need to include at least RMC and GGA sentences. A high sample rate (10hz+) is recommended.

Map

You can change the view of the map by dragging. You can zoom in using your mouse wheel or by pinching on a touch screen.

The map view is currently not configurable. It always shows the follwoing data:

• The line
• Longitudinal acceleration is mapped to the lines color
• Lateral acceleration is mapped to an area extending away from the line.
• Total acceleration is used to color the lateral acceleration area.
• Brake markers, including top speed reached in green
• Slowest points, including minimum speed in red

When comparing laps less data is shown to reduce cluttering

• Lines in the color of the lap
• Break Markers

A very basic satelite view is also available and can be toggled by clicking on .

Video

The video view shows is synchronized with the other graphs. Clicking on the map or channels will seek in the video. Playing back the video will highlight the corresponding sections in the other views.

In a comparison the video view currently always shows the reference lap.

G-Map

On top of the video there is the G-Map. The G-Map is a histogram of the G-Force acting on the vehicle over time. It can be used to gauge how close to the limit one is operating. The circles represent 1, 1.5 and 2 G.

You can click on the G-Map to change through the zoom levels.

Assuming a perfect world where vehicles have isotropic grip, the vehicle sufficient and the rider always at the limit it would trace out a perfect circle, resembling the Circle of forces.

It can be used to see how close to the limit you currently operate and to track your progress over time. You can see if you push harder in left or right handers.

Channels

When comparing laps the data shown in the channels view is aligned to the reference (fastest) lap by matching up the track position. This cannot currently be changed.

The lean angle is currently derrived from the lateral acceleration and does not represent the precise physical lean of the bike.

Lap Selector

In the sidebar on the left you can find the lap selector. On mobile you first need to press to see the sidebar.

In the lap selector you'll see a list of sessions, laps (with number, time of day and lap time).

You can select a lap by clicking on it. You can compare it with other laps by pressing on the laps you want to compare them to.

Filtering

The data shown in the lap analyser is heavily filtered, mostly using kalman filters. It is not raw data but rather an interpretation that could be wrong or misleading. One thing to highlight here is that because the filtering acts a lot like a low pass filter sudden spikes in the data might not be visible.

Feedback & Contact

Feedback is of course very welcome.

Please visit 29a.ch/about to get my contact data.

Blog Post

If you still want to read a bit more about this tool and how it came to be you can also read about it on my blog: Lap Timer and Analyser for GoPro Videos.

Disclamer

There are two things that need to be said here.

First off this is not a perfect solution and even if it was it couldn’t definitely answer the question of how close to the limit the you are operating. Factors like the track surface, weight transfer and other shenanigans are not accounted for and the filtering might hide some information.

Secondly, this product and/or service is not affiliated with, endorsed by or in any way associated with GoPro Inc. or its products and services. GoPro, HERO and their respective logos are trademarks or registered trademarks of GoPro, Inc.

Version

You are currently using version:

0.2.0-0ac123d beta built 2020-07-18T18:12:53.949Z