What is DirtScan all about?

You’ve clicked through the first page, so you’re clearly interested a little bit. Maybe you are a mountain biker, or maybe you are a photogammetry enthusiast - welcome!

Why Youtube videos don’t work

I love mountain biking. I love the thrill of the downhill, the lug of the uphill, and everything in-between. I love exploring, trying out new things, going to new trails.

Not all trails are created equal. Some are well cared for, manicured, interesting, challenging - others can just be kinda meh. As someone with a finite time budget for mountain biking, I want to know where the good trails are so I can spend my time visiting them.

So naturally what do I do? (you probably do this too) - Go onto YouTube, search for [insert location here] mountain bike trails, skim through a few videos and come away with more questions than answers.

Jump cuts of riders doing whips off of tabletops. Head mounted cameras shakier than a thickshake. Fisheye lenses making a mountain seem like a mere bump in the path (a.k.a the GoPro effect).

Videos answer none of my questions.

Enter: Photogammetry

You probably don’t know what photogammetry is. That’s ok - it’s really really simple:

It’s where a computer looks at lots of photos, and works out where they were all taken in relation to one another. Once you know this, you can turn what are 2D photos, into a 3 dimensional model.

That’s the gist. If you’re a nerd you can read more about photogammetry on Wikipedia.

We can use photogammetry to create a 3D model of a mountain bike trail. This means:

There’s no GoPro effect. It’s gone. Really.
Everything is true to scale. You could have a virtual ruler measure it, it’s that precise.
Explore at your pace.

That sounds complicated and expensive?

A goal of the project is to use only really basic, consumer equipment. It uses a GoPro (I know, ironic), and some supplies from Officeworks. I know GoPro’s aren’t exactly cheap, but I figured most mountain bikers (like me) already have one.

The real magic is the code; the program that converts images into 3D models. At the moment, it uses a modified version of the open source photogammetry software COLMAP.

Open source = free, as in freedom. I intend to publish the modified source code once it is… how should I say… working ;)

The road ahead

This is an ambitious project, because it’s a hard project. Doing this with a GoPro is not exactly the well trodden path - others just jump to using expensive equipment and don’t even bother. But I believe it can be done, and I want to do it this way so that it can be done all over the world, by all kinds of different people, as easily as possible.

I don’t want to gatekeep mountain bike trails. I want to help showcase them.

I’m still working on the process, but it’s looking promising. You’ll see updates here when it’s ready.

Until then,

Matt