Objective Evidence – Measuring the Wear

The world around us is constantly changing and always shifting, either due to natural forces, man made intervention, or a combination of the two.

Measuring these changes is part of what photogrammetry is best at. We can quickly quantify differences and changes in everything from buildings to quarrying and stockpiles to seabed wrecks and this is part of what we teach in the AccuPixel Metashape Professional course.

Along with 3D digital reconstruction & preservation one of Simon’s other passions is mountain biking. The sport is hugely popular, delivering wild open space physical and mental health benefits to riders, but like all human activity there can be negative impacts – one of which is accelerated trail erosion.

Digital Elevation Model of the trails. The trail running north east is of concern

Objective Evidence

Mountain biking trails tend to be narrow – just 30cm wide in places – and the knobbly tyres spread the load of rider so overall impact can be light but two recent events have seen a section of local trails see increased erosion:

  • COVID lockdowns has seen more riders enjoy and use the lands
  • Recent periods of extended, heavy rainfall have saturated the lands

The combination of the two have combined to increase erosion in a few very localised areas. Visually we can see the changes…and intervention may be necessary…but just how much has eroded?

When compared to the overall trail network – running to 100s of kms – the impacted areas are statistically insignificant but the sport has to recognise the negative impact and, when required, be prepared to carry out restorative work to address the issues

These kind of questions are being asked by many recreational users and landowners – so could photogrammetry provide the answers?

A short drone flight gathered the images of the area and whilst the vegetation cover was prolific the trails stood out enough for Metashape Professional to align the images.

Measure the Changes

Metashape Professional analysis tools have helped us understand how the trail is today. We can provide anyone who needs to know accurate measurements revealing the current state of the trail as of the 18th August 2021.

The first drone flight and subsequent processing has established a baseline – a digital copy – of the trail.

Objective vs Subjective

Measuring mountain biking and its impact on the environment is important and can act as a guide to what and where the issues are. Landowners can be hostile to the mountain biking community but this kind of objective information can either highlight very real concerns, or explain and demonstrate MTB is causing minimal harm.

In 3~6 months we can repeat the flight and gather a second set of images, build a second model and compare the changes using the two DEMs – this is something we teach in our Agisoft endorsed Metashape Professional training course.

Removing subjectivity from the debate about mountain biking being good or bad is very much the correct thing to do. By focussing on the real as opposed to perceived issues both landowners and riders should be more willing and able to reach a common understanding and positive working relationship.

Such is the power of photogrammetry.