Scanning the 2nd largest cave chamber in Europe. Commendium have deployed their 3D mapping systems in several caves around the world and we were invited back by the Karst Institute in Postojna, Slovenia to complete a 3D survey of the Skocjanske Cave system. As a part of a UNESCO World Heritage Site, the data was required for geological studies and an appreciation of the state of the cave for monitoring purposes. On one wintery morning in January we set off via the ferry to Skocjanske in Slovenia which boasts the world’s finest portfolio of amazing karst caves. Karst caves are known for their delicate ecosystem and exhilarating topography and the region around Skocjan is seen as the home of Karst geology. The brief was to monitor the condition of the cave and take measurements using highly accurate 3D LiDAR, then build digital models of the caves. After a calm ferry journey and a long drive, we reached Slovenia and were pleased to see our hosts, who are now becoming like family. After a good sleep, we gathered the team and set off excitedly. With the Reigl Scanner, batteries, photography kit, caving gear, and the drone all weighing in excess of 30kg, we started on the 2-hour walk to the Martel Chamber. John Nelmes was particularly excited to be on his first trip to Slovenia with his drone, but not so excited when he saw the cave entrance and the 70m sheer drop. We finally reached the chamber via 1.5 km of narrow paths, hacked into the sides of caves by original explorers followed by 4 rope river crossings and lots of traversing on ledges. During the expedition, we found that the Martel chamber is, in fact, the second largest cave chamber in Europe, and 11th largest in the world. Skocjanske Cave System Flood A few days after our trip, a huge thaw saw the river rise from 2 cubic metres of water per second to a peak of 290, flooding the chamber where we had been working to a depth of 90m. There was no danger, this cave is the most monitored cave in the world, there was no risk of being marooned. The results will take a year or so to process but already three scientific papers are underway. The survey is also being used to assess the feasibility of establishing other tourist paths within the cave. Overall, Commendium's Slovenia trip to the Skocjanske Cave System was very successful and…
Sonar surveying the floor of a flooded quarry Usually, you will find us below ground scanning or climbing through to the next cavern with a huge amount of scanning equipment, not carrying out SONAR surveying from the back of a boat in winter. This morning we set out to map the floor basin of Capernwray, a former quarry, now flooded and used as a dive centre. The reason for this early start and rubber dingy journey is to test out a new sonar rig to ascertain if it’s going to deliver the results we need for upcoming bathymetric surveys of several tropical rivers. The rig loaded and ready for use today is the StarFish 452F; for those of you who are technically inclined, the starfish is is a high-frequency side-imagining, sonar device. The starfish is an unusual design with hydrodynamic three fins, it differs greatly from the common cylindrical torpedo shape side scan of many sonars. [caption id="attachment_210" align="aligncenter" width="200"] The Starfish 452F[/caption] With the StarFish - 452F loaded safely and attached to a rope of 10m, we set off across the quarry lake to test the range and resolution capabilities of the imaging device, which promised us wide range imaging of 100m per channel, which is 200m total swathe coverage. The surveying process The sonar surveying took us approximately 20 minutes, with a distance of 0.5 km. With the data safely gathered we rushed back with the data to see what this compressed high-intensity radar pulsing bit of kit could deliver, and would it be enough? Safely back in the office, we launched the data and saw some very convincing and highly detailed scans produced. Overall, we were indeed happy with the Starfish side scanner, which had picked up several artifacts in the lake including a sunken plane. The detailing of the plane wasn’t high resolution, but the floor of the lake and side facings were captured in full quality, which is exactly what we need from the Starfish. We are now working on programming methods to turn this data into a 3D image of the lake floor. View the video below to find out a little more about the process:
Commendium CEO, Richard Walters, has been back in China surveying the world’s largest cave chambers in 3D. Using the latest LiDAR techniques he and his team have been revealing the true nature of some recently discovered huge caves in Guangxi and Guizhou provinces. His team resurveyed the world’s largest cave chamber, The Miao Room and found it to be even larger than previously believed. At almost 11 million cubic metres it is about ten times the size of Wembley stadium. Giant Sinkhole Of more note, was the survey of a seemingly small hole, called Maoqidong, situated about 10m from an important road through the mountains near a town called Leye. That there was a huge cave below was clear, as warm damp air condenses as it leaves the hole leaving a signature column of steam rising from the ground. The survey confirmed it was an immense 260m to the floor of the cave. A further 200m down a steep slope to an underground river showed, for the first time, the chamber to be an immense 6.2 million cubic metres in volume. Alarmingly, the road was found to be a mere 4m from this underground cavity. Richard produced a detailed report for the local authorities to highlight the road’s precarious position above the invisible void below. This giant sinkhole could have caused major problems for local infrastructure. Surveying Technique The mapping technique involved 3D laser scanning from selected stations around the cave and on the surface near entrances. Then on return to the base camp, stitching all these scans together using specialist software. Commendium used its own methods and tools to reduce errant points and generate clean point clouds from which geo-located 3D models were produced. To find out more about how we do this, please take a look at our LiDAR scanning services or Contact us.
Commendium are currently partnering with Wardell Armstrong in providing detailed archaeological recording using drones for certain archaeological sites along the route of the proposed HS2 High-Speed railway. We have developed a process that allows us to capture not only video and photography for each of the sites but also elevation maps, orthomosaic maps, and 3D photogrammetric models. The data we are collecting is invaluable in determining if further investigation is needed in the areas but also allow for archaeologists to find new and hidden features. On a recent survey, we were asked to assist the BBC in filming for a new documentary using our drone. This was because the permissions to fly over the sites is so tightly restricted that we were the only company with authority to perform this. As these are active working sites, Commendiums surveyors have successfully applied for CSCS cards and qualifications to become authorised for construction site work. This has opened up a new avenue of work for Commendium and we are currently testing how to use photogrammetry within the construction industry. Our photogrammetric and LiDAR services are able to quantify the mass of excavations, provide detailed location data for constructions and accurately measure buildings, rivers, ditches and more. Aligned to the drone technology, we are able to carry out this work much quicker than traditional methods and much more accurately. More archaeological recording using drones surveying for the HS2 project is coming in and we expect our involvement to continue over the next few years. The project does present some challenges for us, but our team of specialist are able to overcome this by providing a completely bespoke service. In this project, the flight plans are generally pre-determined, but room is left for changes when on site. An example of this is a recent site that had a number of red kites within the boundaries of the surveying area. An ecologist was on hand to check the nests and to advise our drone operator of any potential issues. In fact, during one of our flights, we can see one of the red kites fly within about 20 feet, but the bird of prey completely disregards our drone. Have a look at what more we can do: Aerial Surveying, LiDAR sruveying