The Maistra group and using LiDAR for site documentation
Whether you are cruising down the Adriatic coast, visiting the famous Game of Thrones filmsets in Dubrovnik or experiencing some of Croatia’s famous cities; with visitors to Croatia more than doubling since 2010, tourism has become an important part of the Croatian economy.
In the North sits the Istrian peninsula, a place known for its beauty, history, amazing food, and a place tourists flock to year on year both domestically and internationally. A sharp increase in visitors has meant that tourism sector has needed to adapt to the exponential growth.
The Maistra group is one of Croatia’s leading tourist companies. They manage 18 hotels, 11 tourist villages and 6 campsites in sought out destinations such as Rovinj, Vrsar, Zagreb and Dubrovnik. With so much property to manage, they need quick and efficient ways to keep their site documentation up to date. In early 2021 they approached GeoSLAMs Croatian dealer, Geocentar, requesting a scan of one of their campsites in Rovinj on the Istrian peninsula.
Working with the ZEB Horizon in Rovinj
Due to the size of the site, 1100m x 700m, the team at Geo-Centar opted to tackle the scan using GeoSLAMs ZEB Horizon, plus aerial photogrammetry. The aim of the survey was to create up to date campsite documentation in the form of 2D vector maps, high resolution 2D raster maps, georeferenced imagery, and a digital terrain model with contours. As a result of the campsites age and need to modernisation, the documentation will serve as a reference for design purposes.
Combining both high resolution orthophotos of the area with the point cloud from the ZEB Horizon, the team were able to capture data quickly, accurately and without disruption. By utilising the walk-and-scan method of capturing data, they were able to make light work of the task.
Being able to walk and scan is a true blessing in such situations since any other scanning method is either much slower or much more expensive.
In total, 10 scans were conducted which mainly focused on buildings, terrain covered with vegetation and other objects that would be tough to capture with aerial photography. Each scan took approximately 20 minutes, so the team were able to cover the entire 1100m x 700m in just over 3 hours. Using the scans, the team were able to extract roads, sports fields, fences, stairs buildings and roads.
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Accurately Mapping Informal Settlements in Bengaluru, India
The informal settlements in Bengaluru, India, house roughly 16% of the city’s population and there are around 500 recognised in this area.
Currently, Bengaluru is going through a period of modernisation and urbanisation which has caused the city limits to expand. As a result, the local government must provide documents of every house, detailing accurate measurements of its structure, such as boundary lines and roof heights.
The government has plans to formally declare ownership of the settlements to the people living in them, which means a map of the whole area was needed.
The Informal Settlements Narrow Lanes and Changing Environments
A team from a reputed geospatial company appointed by government, surveyed the area and collected this data. This involved mapping the informal settlements in Bengaluru with their complex layouts. The task was challenging as they include many narrow lanes that are difficult to access. Additionally, people were going about their daily activities.
Furthermore, some parts of the settlements are in dark and cramped areas whereas others are in direct sunlight. Consequently, the team needed to find adaptable solutions and technology that could handle these difficult environments, as well as deliver on the task in hand.
The area in question is a no-fly zone, which meant that drones were not an option. However, other methods for capturing data such as static scanning wouldn’t be feasible because of the busyness of the area. The cramped streets also meant the team would struggle to use a backpack solution either.
Scanning Difficult to Access Areas with ZEB Horizon
A fast and effective way to map the informal settlements was to walk through the complex passages, and a handheld laser scanner was the most suitable option. The geospatial company chose GeoSLAM’s ZEB Horizon scanner, due to its quick method of capturing accurate data and ease of use. The lightweight solution means that only one person is required to scan an area at any one time. This is less disruptive to the surveying team, which in turn is cost effective for them and their client.
The extensive maze of restricted passages and dead ends did not affect the versatile SLAM technology. By using the ZEB Horizon, the team were able to scan 40-45 different areas of the settlements. The team captured smaller areas of the informal settlements in a single scan ranging from 25-27 minutes. The team mapped larger areas over multiple scans, sending them to the client individually.
The ZEB Horizon provided good quality data and allowed us to scan difficult to access areas accurately and efficiently.
Creating accurate point clouds for the client
The final scans were imported into GeoSLAM Draw where orthophotos were automatically created. As a result, the engineers could make accurate measurements in a timely manner. In addition, the point clouds were exported to Terra Solid, where further information was extracted for the final report.
The final data delivered on their client’s accuracy goals. They were able to smoothly extract the boundaries and roofs of every single house in the informal settlements.
GeoSLAM’s technology in use elsewhere
This is not the first time that GeoSLAM technology has been used to map informal settlements in India. The ZEB Revo was used to accurately scan the settlements of Mumbai in 2017. The resulting 3D point cloud helped to extract information about the elevations and sections of each house frontage.
In this blog I am going to talk about the various locations we visited, and show the data we captured from historic locations around the country.
Grand Caverns |History, geotourism & science
Discovered in 1804 by Bernard Weyer in the heart of Virginia, Grand Caverns (formerly Weyer’s Cave) is the oldest show cave in the USA. During the US civil war, the cave was used by both Confederate and Union soldiers as part of the Valley campaign, during which time over 230 soldiers signed their names on to the cave walls. More recently, the cave has become a huge tourist attraction, due to its beauty, location and being surrounded by scenic trails for hiking, running, and biking, but it has also captured the attention of the scientific community because of recent discoveries of new passages and the rock formation changes over time.
The town of Grottoes (where the show cave is located) partnered with Angel A. Garcia Jr. and his students from James Madison University to create a 3D map of the cave. The 3D point cloud is being used to measure Speleothems, monitor the human impact on the cave, create 3D printed models and to celebrate the show cave’s extensive history, shining a light on its geoheritage. In addition, it is a fantastic opportunity for the undergraduate students of JMU to get hands on experience with the handheld LiDAR scanner and the data it outputs.
Angel A. Garcia Jr. chose GeoSLAM’s ZEB Horizon scanner to take on the task of mapping both the parts of the cave open to the public and the recently discovered, vast passages. He and his students capitalise on the speed of capture and accuracy of the scanner to review and analyse data in a quick and efficient manner.
With the LiDAR we’ll be able to get into corners and see what hasn’t been looked at for a long time.
Mobile Mapping with the ZEB Horizon
Having originally purchased the ZEB Horizon back in February 2021 to collaborate and share data with partners scanning caves using ZEB devices in Puerto Rico, Professor Garcia began to see the potential and opportunities the scanner offered. Fast, accurate and handheld data capture opens a way to map an area without the need to GPS or complicated setups. In addition, the scanners ease of use means that undergraduate students can be involved in the project with limited to no training.
Since beginning to use the ZEB Horizon, interest in Professor Garcia’s work with the SLAM scanner has escalated, and he has subsequently been invited to other universities to run workshops. In April 2021, he was approached by Grand Caverns to map the historic show cave.
The public area of the cave is approximately 500 meters in length, 30 meters high and has stairways in places, so it is quite a large area to capture. Professor Garcia and his students were able to capture the entire public area in approximately 12-15 minutes, by simply walking and scanning. He pointed out that a terrestrial laser scanner would be able to capture the public part of the cave, but it would take days, not minutes, and due to the uneven surfaces of the non-public area of the cave, it would be impossible to get a tripod-based system down there. Alternatively, you could measure a cave using a distometer, but this could take months, if not years to complete.
The ZEB Horizon was able to give them a quick accurate scan in 12 minutes, so the students could get to work reviewing the data for their various projects.
It’s going be able to detect the stalagmites, the stalactites and it’s even going to be able to detect the cave shield because it’s that precise.
The data is being processed using GeoSLAM Hub, and Draw is being utilised by the team to accurately measure the speleothems over time. The students can see the orientation, thickness and gather measurements using the LiDAR information alone. They are also hoping to use Draw to understand accurate dimensions of the cave. Furthermore, the 3D point cloud is being used as a base to 3D print the cave within a rectangular block, for further research purposes.
The team continued to scan the cave over the summer, and Professor Garcia is working with the caving/spelunking community of experts to begin capturing the more problematic and recently discovered new passages of the cave. These areas have not designed for the public at the moment, so there are uneven surfaces and narrow corridors, but due to the ZEB Horizons mobility, capturing previously unseen parts of cave will be quick and safe.
Professor Garcia concludes by saying that the 3D model will provide an opportunity for those who can’t physically enter the caverns, to learn what they are all about.
GeoSLAM were invited by Willmott Dixon to be involved with the beginning of this process, by scanning the existing used timber units provided by Carter Accommodation. Using the ZEB Revo RT, Willmott Dixon were able to capture data of all 4 cabins, in 4 minutes, registering over 8 million number of points.
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