Points of Interest

The Vobster Photogrammetry Project gives us the perfect excuse to test new techniques as it throws up new 3D reconstruction challenges. Its fair to say UWIS GPS driven underwater navigation and position recording has enabled a huge jump forward this year even with COVID restrictions limiting us.

UWIS at Vobster

Back in the Deep

Last Wednesday we found ourselves back at Vobster Quay with the intention of recording the underwater location of every buoy line. Divers Rick and David given the task and tablet both as means to navigate to targets and mark their GPS location. The tablet is loaded with the site ortho photo delivering a live view of where you are delivering a very rich and relevant context based tool for finding your way around a site.

The Altab tablet with Valtamer navigation software. Image courtesy Rick Ayrton

Those topside get a view on progress via the UWIS Tracker software. It was very satisfying seeing the dive track appear as Rick and David went from attraction to attraction. The topside brief had not included an introduction to two-way communication but on the way back we couldn’t help alerting the team to the presence of a shark…

Each attraction and buoy line visited in turn and aided by the tablet. There are no sharks in Vobster…

In less than an hour the buoy lines were recorded now giving us a fix on where each buoy is anchored. These values can be compared to the surface survey and whilst the buoys are very much dynamic their movement is limited. We can start to compare the results and repeat the exercise with UWIS again to record GPS drift. All round a very productive dive.

Logging the position of the caravan buoy line. Image courtesy Rick Ayrton

Seeking the Subject

There were two tasks for the second dive; locate the Humber car and record its position and then see if any of the White Clawed Crayfish could be located.

Protected and and listed as an endangered species the White Clawed crayfish is in steep decline following the introduction of disease carrying Signal Crayfish. Vobster is acting as an ark for these incredibly rare and vulnerable species and knowing where they are living is useful to those studying them.

After locating the Humber and recording its position Rick and David set out for known crayfish sites – a navigation task made easier by the tablet – and precisely 58.49m from the Humber – a crayfish was spotted and recorded on both the tablet and on camera.

A White Clawed Crayfish in Vobster. Image courtesy Rick Ayrton

Navigation Made Easy

UWIS always draws the attention of other divers and on seeing the diver trail on the laptop screen one declared they could “sell their compass”.

Like all technology having a backup is vital so selling the compass might be inadvisable. But we are now entering a golden age of cost effective GPS driven underwater navigation. For the efficiency of underwater searching, recovery and recording it’s about time.

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