ZEB Horizon used to Capture data on Croatia’s forest to understand biomass
1km in length
Geocentar | Words by Luka Zalovic
“47% of Croatia’s total land area is covered by forest, an area of approximately 25,000km2 . Management of these vast valuable assets is a key industry in Croatia and across its central European neighbours. As well as managing the biodiversity and sustainability of the forests, it is important for commercial logging companies to assess the quality and biomass of the forests for responsible timber sales. This assessment is a growing need – every year, Croatia adds 10.5 million m3 of forestry to its stock.
Methods of forestry management typically involve measuring the height, diameter and relative position of trees using equipment such as tape measures, ultrasound instruments, total stations and terrestrial laser scanners. However, there are limitations to these methods – they’re often time consuming, involve multiple setups and numerous members of staff to take the measurements (especially since forestry is usually in remote and difficult to access areas). Due to dense canopy cover, forests are usually GNSS-denied areas, and along with the uneven terrain, it can be difficult and time consuming to measure with terrestrial laser scanners.
Geocentar have a large client base in the forestry industry and upon delivery of our new ZEB Horizon mobile laser scanner, we decided to put the technology through its paces and see how it weighs up against other solutions for measuring biomass.
“The ZEB Horizon captures forestry data more accurately than traditional methods and eight times faster“
Visiting the Perivoj Zrinskih park, the ZEB Horizon was initialised on a flat surface before the operator navigated around the park at normal walking pace. With a capture range of 100m, It took just 9 minutes in total to walk around the park and capture all the trees.
Back in the office we processed the data with GeoSLAM Hub software, then exported using GeoSLAM Draw. The data was then imported into an open source forestry programme called 3DForest whereupon several parameters could be measured and extracted automatically including ground extraction, tree detection, tree position detection, tree radius determination, tree height determination, tree crowns detection, crowns volume calculation and crowns collision determination.
Later we revisited the park to check the accuracy of their results and re-produced the survey using a total station with built-in REM (Remote Elevation Measurement) and a measuring tape. Not only did it take four minutes per tree to capture data due to all the total station setups, but only four parameters (diameter, height and relative position) could be calculated using these methods. If they had attempted to measure all 217 trees, it would have taken a whopping 14.5 hours!
Using the ZEB Horizon and 3DForest software, it took 9 minutes to scan the park, 12 to process the data in GeoSLAM Hub, 5 minutes to reduce the data size in Hub and prepare the cloud for the forestry software, which took 90 minutes to process. The total workflow took just under two hours to collect and measure all 217 trees – using traditional methods they could have surveyed just 29 trees in this time.
Geocentar calculated that results were accurate to within 3cm and were more accurate than using traditional methods, leading to great cost savings.
Using LiDAR to understand complex forest environments
10 mins per scan
1km in length
University of Leicester | Eden Project
Monitoring and understanding our environment has never been more important as the threat of climate change looms and governments step up to better manage their greenhouse gas emissions. Tom Potter, a doctoral researcher at the University of Leicester, UK, set out to further develop a technique to estimate biomass and carbon more efficiently using state-of-the-art, mobile LiDAR sensors across multiple, complex forest environments.
To do so he visited the Eden Project in Cornwall, UK which reflects a true tropical forest – representing different forests from around the world with a rainforest ‘biome’ of over 1,000 tropical trees and plans. However, he had to work around several challenges. For fixed point scanners, the high-density plots of specimens created a problem of shadows – known as ‘occlusions’ – whereby the nearest features will block out features behind. This also limits the ability to acquire accurate measurements to create a comprehensive 3D model. And with the biome being open to the public and a popular tourist destination, Tom only had a few hours each day before opening hours – insufficient time for a traditional static survey.
“Using GeoSLAM’s local processing software, the raw scan data was processed on site, with no internet connection required – useful when in an actual rainforest!“
Mobile surveying equipment that was able to take readings easily and quickly from even the densest areas was needed to ensure precise scans were taken to accurately calculate biomass and carbon storage potential.
Tom found the mobility and speed of GeoSLAM’s ZEB Revo to be the perfect solution. The lightweight scanner can be pole mounted, handheld or even attached to a vehicle or drone – collecting over 43,000 measurement points per second. Instead of hundreds of time-consuming static scans, Tom captured all angles by simply walking in a loop around the rainforest environment.
He then converted the point cloud data into 3D volume-based plots to derive above-ground biomass and carbon densities for multiple types of tropical forest. A comprehensive dataset was built, containing information for any type of forest that scientists can use to make calculations with minimal survey effort or expertise. And all at considerably less expenditure than traditional survey methods.
Choate Construction utilizes GeoSLAM to create floorplans for hurricane damaged properties
7 mins per scan
111,000 sq ft
Choate Construction | Construction company
2017’s Hurricane Irma was the most powerful storm to hit the continental United States since Katrina in 2005. Besides the high human cost (almost 100 lives lost in the US) the financial cost to property was estimated to top $50 billion – the 5th costliest hurricane in US history.
Amongst those damaged properties were the Westlake Apartments in Savannah, Georgia – a complex of 14 buildings containing 100 individual apartments encompassing over 111,000 sq. ft. These residential structures were flooded by the storm surge – meaning major renovations were required to repair the significant water damage.
With the complex dating from 1974, no building blueprints were in existence. The huge task facing contractor Choate Construction was therefore to rapidly collect this spatial data to produce the necessary internal floorplans and external elevations. Utilizing a static scanner was out of the question as to capture all necessary data would have required over 1,500 individual set-ups – at an estimated timescale of 3 weeks.
“This would have taken over 75 hours of scanner time along with a static scanner, with the ZEB Revo we were able to accomplish this in only two days“
Mobile, handheld mapping was therefore the ideal solution – chosen for its incredible speed and ease of use. Instead of 1,500 scans, just 14 scans were required (one scan per building) to collect the necessary building elements (floors, walls, ceilings, rooves, doors, and windows) within the required accuracy tolerance.
The Choate Construction team utilized the ZEB Revo to complete the job. With individual scans as quick as just 7 minutes, the average scan time was 40 minutes per building. In total, the team spent less than 10 hours scanning – spending just 2 days on site.
This speed was of particular importance as the residential units were in occupation – with a scan time of just 5 minutes per unit, disruption to residents was kept to an absolute minimum.
The survey team were delighted with the high reliability of the scan data, all within 1” relative and absolute accuracy. They were also surprised by how well the external features (exterior walls and sloped rooves) were captured – with no drift or errors encountered.
The 3D scan data was quickly processed in GeoSLAM Hub – a one-stop shop for point cloud manipulation.
The office team were able to view the individual 3D point clouds, as well as merging them into one. The data was also sliced into plans, sections and elevations within GeoSLAM Draw, and exported in a CAD-friendly format. From this data, an accurate 3D Revit model was built and supplied to the project architect.
With the increasing incidence of ever-more powerful tropical storms, and an ageing property stock, such quick and simple survey solutions are surely the way of the future
There is no doubt that historical projects hold great significance for a location’s cultural heritage and its people. This is the fundamental concept that Historic England apply in their protection and conservation of sites that define English history and the nation itself. They work within communities and alongside specialists to share their knowledge and skills so that everyone can enjoy and maintain the history that surrounds us.
This is evident in Historic England’s Ramsgate Tunnels project, a five-kilometre network of underground passageways which were paramount to the war effort and the safety of local people of Ramsgate, Kent.
Ramsgate Tunnels were once used as an underground narrow-gauge railway, built to connect the town and docks to help improve trade links to Europe. However, the railway soon became a target for enemy bombing. To combat this, it was decided that the network of tunnels should be adapted to protect the people of Ramsgate, and work on this began in 1939.
“GeoSLAM technology was at the top of our list to scan the underground network, primarily due to its long range capabilities”
After falling into disrepair, leaving behind a long-existing collapse in one area of the tunnels, our team at Historic England was invited to work alongside Ramsgate’s Heritage Action Zone in order to redevelop the area’s much-loved historical sites. Enlisting the help of GeoSLAM’s ZEB Horizon to provide a preliminary map of the damage, plans were put in place to assess tunnels that were previously inaccessible in order to extend visitor access.
The ZEB Horizon allowed our team to reach further down each channel where we needed a quick overview of the extent of the damage, and its approximate location relative to the surface. A total of nine scans comprised the complete survey, taking around 10 minutes for each scan. Compared to a static scanner, GeoSLAM’s ZEB Horizon improved the speed of the scanning process dramatically
Placed first in Australia and 20th in the world, Australian National University (ANU) is a research institution with its main campus in Canberra, the country’s capital. The university’s research priorities typically reflect the challenges facing the world today. One such project is to track tree growth and development over time in a joint effort between ANU and Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO).
Known as the ‘Precision Measurement of Trees and Forests’ project, the field team is charged with comparing and contrasting different ways of collecting data, using different terrestrial and airborne laser scanners, and working with digital imagery. The survey takes places in the National Arboretum in Canberra which features some 44,000 rare, endangered and symbolic trees and is made up of 94 mini forests.
GeoSLAM’s “go-anywhere” mapping technology was a natural choice for the outdoor project. Unlike terrestrial systems, the splash-proof, dust-tight, mobile laser scanners are designed to operate in the most difficult-to-access spaces, inside or outside, in daylight and darkness – without the need for GPS. What’s more, you can easily attach the portable laser scanners to a drone or helicopter for fast outdoor surveying.
In addition to GeoSLAM’s versatile handheld technology, the team also uses fixed point scanning and traditional forestry measures – such as Suunto and digital photographs from UAV’s. Tom Jovanovic, former CSIRO researcher and now Interactive Technology Specialist at the University of Newcastle, Australia, explains that the technologies are complementary, “Using GeoSLAM from the outset, as well as a different system, has enabled us to compare and contrast different measurements and combine them into a heavily monitored site finding. This includes the high level of resolution being sought.”
“What I really like about this product is that wherever you can walk, you can scan. It really is a case of ‘go-anywhere’ “
Emphasising that the project is specifically designed to take advantage of both static and mobile approaches, Tom Jovanovic says, “What’s nice about scanning with GeoSLAM’s technology is that it doesn’t involve repeatedly setting up in different locations within the research plot. You just initiate the start-up procedure then walk around the plot covering the trees from different angles.”
All forestry professionals like Tom need access to user-friendly technology that is easy to operate but is robust and reliable enough to do the job quickly and accurately. With GeoSLAM scanning technology, he says it takes only 10 to 15 minutes to completely cover a 180 square meter plot, adding, “What I really like about this product is that wherever you can walk, you can scan. It really is a case of ‘go-anywhere’. The scanner has made a significant contribution to an important undertaking. Mobile scanning that gives us dynamic changes over time – from any angle and in 3D – is a very important contributor to this work.”
“Mobile scanning that gives us dynamic changes over time – from any angle and in 3D – is a very important contributor to this work“
These GeoSLAM-delivered findings are vital to the project’s long-term aim. Combining them with knowledge of water usage and photo synthesis, plus meteorological data and high resolution photography, they feed into very fine scale modelling that will guide forestry research management and habitat protection policies into the future.