Preserving a Roman ‘Billionaire’s Villa’ with 3D laser scanning

Author: Paula Noriega Fernández

An expansive Roman villa in Cuenca in central Spain, “Villa Noheda,” is an important archaeological site and home to one of the largest ancient mosaics in the world. It is looked after by Castilla La Mancha Provincial Council, who asked Spanish surveying firm ABSCISA 3D to help create an up-to-date and complete digital record of the site as it stands today. ABSCISA 3D chose to use a Leica Geosystems 3D laser scanning solution to create a three-dimensional reconstruction of the rural complex, working alongside archaeologists from Global Arqueología. The collected point cloud data will be compared with previous studies to track preservation work over time.

Capturing pieces of history: multiple phases of excavation at Villa Noheda

Considered an Asset of Cultural Interest (BIC) in Spain, Villa Noheda is managed by the regional government in Castilla La Mancha. The site was discovered by chance in 1984, when the then landowners were preparing the ground for crops. They found a mosaic which has since been uncovered to show six mythical scenes surrounded by geometric and plant decoration, roughly 300 square metres. Intensive exploration wasn’t carried out until 2005 and subsequent excavations have continued to make new discoveries including a series of rooms, a fountain and a spa. The latest survey by ABSCISA 3D will provide Castilla La Mancha Provincial Council with a record of the existing excavations for future study.

Using a Leica RTC360 3D laser scanner for fast, precise data capture

For their work at Villa Noheda, the ABSCISA 3D team chose to use the Leica RTC360 3D laser scanner, “for the good relationship between scanning times and the high precision of the result,” explains Paula Noriega Fernández, engineer surveyor. “Weight also influenced.” The RTC360 is highly portable, ideal for a rural site, and captures detailed scans, including enriched High-Dynamic Range (HDR) imagery, in less than two minutes. For data capture in the field, ABSCISA 3D used the Leica Cyclone FIELD 360 mobile app. With Cyclone FIELD 360, users can visualise their results immediately; it automatically pre-registers point cloud data to enable users to quickly conduct on-site quality control checks.

Back in the office, ABSCISA 3D used Leica Cyclone Core and Leica Cyclone 3DR for point cloud processing. Noriega Fernández explains, “With the Leica Cyclone, we imported the data from the laser scanner and registered the point cloud. Cyclone is safe and stable when it comes to handling a large number of point clouds. We always work with Cyclone.” She continues, “We unify and export the data in .e57 format. With Leica Cyclone 3DR we make the digital elevation models and the topographic plan, which serves as the basis for the work of archaeologists.”

“The time in the field is very fast, this makes the cost of the work lower”

Noriega Fernández used the RTC360 to obtain detailed point cloud data which will be used in multiple ways. She says, “we were able to obtain a dense point cloud that allows the calculation of the orthophotography and a three-dimensional model of the reservoir area.”

The speed of the data capture - up to 2 million points per second - is a real benefit to the business, says Noriega Fernández, “We have verified that the time in the field is very fast, this makes the cost of the work lower.” Portability also contributes to keeping costs under control because the work only requires one surveyor: “This type of work is done by one person. This saves on personnel.”

As well as being fast, the RTC360 laser scanner offers precision that can be checked directly on-site via Cyclone FIELD 360. Low noise data allows for crisp, high-quality scans that are rich in detail and ready for use in a range of applications. Noriega Fernández continues, “We always recommend the RTC360 3D laser scanner for these types of jobs. Its speed and precision are incredible.”

Cyclone CORE: “Incredible software when it comes to working with the point clouds”

Once the field work was complete, the ABSCISA 3D team used Cyclone software for final point cloud registration and export to Cyclone 3DR. They then created the final deliverables, including a Digital Elevation Model (DEM). She explains, “The point cloud is the starting point for subsequent work, orthophotography, mapping, MDS, point cloud comparison of various work campaigns. Archaeologists need the DEM to know the heights of existing walls relative to mosaic and natural terrain, as well as the slope of the terrain. They study it and make the interpretations.”

“The point cloud also serves as a database for future jobs, and needs that the administration may have and leaves a documentation of the heritage. Cyclone seems to us an incredible software when it comes to working with the point clouds.”

An all-round solution for 3D laser scanning: “We believe that it is a very complete product”

Although it is an extraordinary site, the survey at Villa Noheda was in many ways a normal job for ABSCISA 3D. Noriega Fernández says that ABSCISA 3D uses the RTC360 in 95 percent of their field work, from scanning ancient ruins to 1970s houses ready for remodelling and from bridges to large industrial plants. “We use the RTC360 laser scanner for most jobs, both heritage, building, industrial and civil. We believe that it is a very complete product.”