This left China shrouded in grief, but not for long as the survivors chose to live strong in honor of loved ones who have perished in the disaster. In a matter of days, numerous memorial sites sprouted like mushrooms after a spring rain, taking on various forms and sizes, set up either in memory of the lives lost or to commemorate the fighting spirit that unified the people of China and beyond. Other commemorative sites delved into the research, educational and aesthetic value of the aftermath that the quake left behind. One such Earthquake Memorial Park is located in Chuanxindian Village of Shifang City, Wenchuan County.
While this is but one of the many physical reminders of the adversity the Chinese people have endured, what sets the Wenchuan Earthquake Memorial Park apart from the rest is its high-technology focus. Right from the beginning, the project initiators, Beijing Institute of Surveying & Mapping, had planned to acquire and use three-dimensional (3D) images for various parts of the memorial. The project is also particularly significant because it is the largest life-sized 3D virtual reality scan of any subject matter, both domestically and globally.
The team behind the memorial designed a comprehensive study using a multi-pronged approach, involving high-technology equipment in many areas. Mr Yin Wenguang, Project Leader from Beijing Hao Yu World Mapping Technology Development Co., Ltd. shared, “We used an unmanned aerial vehicle to collect data from a bird’s eye view. And on the ground, we employed laser scanning technology, precision control measurement technology, and close range photography to gather a wide variety of images for full digital reconstruction of the site.”
FARO Laser Scanner Photon 120 offers high-speed and high-accuracy scanning for the memorial park in Chuanxindian, Wenchuan
When portable 3D measurement company FARO first heard about the project scope, it was immediately keen to support. As a global technology company that develops and markets computer-aided coordinate measurement devices and software, FARO is recognized for its portable equipment capable of high-precision 3D measurement and documentation. FARO was confident of being the perfect complement to the project as the area of investigation was well within its expertise. After a live demonstration of the product, the company was enlisted to be part of the nearly year-long project. “We were thoroughly convinced that FARO’s Laser Scanner was what we needed to complete the ground scans,” said Yin.
3D Documentation of Earthquake Ruins
According to the project design, the scan results were meant to serve as a comprehensive digital archive of the aftermath. The complexity of the damage, as well as how it is characteristic of a quake, implies that much can be learnt from it. Research and education are two main forms of motivation for documenting the damage and revisiting it. With FARO onboard the project, high quality 3D scans were obtained and reproduced easily with the 3D Laser Scanner, Photon 120.
Using the free-station positioning method, researchers employed the Photon 120 to collect point cloud data for the Industrial Ruins Zone and the Earthquake Relief Memorial Square. To ensure integrity of data gathered, the team limited the distance between measuring stations to less than 25m and insisted on an overlap in scan range of at least 25%. Care was also taken to ensure point cloud accuracy, by controlling the angle between the laser beam and the normal, ensuring that it is less than 45°. In addition, the distance between the target and scanner was limited to a maximum of 15m, with range accuracy kept at 2mm. Finally, scan resolution parameter was set at 1/4 with sample spacing maintained between 1~9mm to maintain appropriate point cloud density.
3D coloured model of Chuanxindian Industrial Ruins in Wenchuan
When asked about his experience in the usage of FARO 3D Laser Scanner, Yin expressed, “The scanner gave us exceptionally accurate scans in a very short amount of time. Its ease of use helped us complete the necessary surveys and generate the 3D model outputs efficiently.”
After seven months of data collection and processing, the team reconstructed a comprehensive digital archive of the core zone that totaled an impressive area of approximately 0.3km2. This included both the Wenchuan Earthquake Memorial Park, as well as the Earthquake Relief Memorial Square. Using multi-source data processing, the team managed to corroborate the various sets of images to produce point cloud models and 3D coloured models that have had coordinates registered and transformed.
Aside from serving as an archive, the scan results will be used for several other applications within the memorial — such as in the overall layout plan for the park, as a virtual tour system for an exhibit, and even as a 3D-video for tourism marketing.
3D point cloud model plotted with registered and transformed coordinates
The Wenchuan Earthquake Memorial Park exists not just to remind the locals of the tragedy. As an educational site, it seeks to inform the public of lessons learnt from the incident, in the hope that future generations can minimize loss of lives in similar disasters. “FARO is very honoured to be part of this meaningful project,” commented Mr Xin Ning, Account Manager from FARO China. “Virtually walking through the town in the life-sized 3D model allows one to feel as though one was physically there. I believe our involvement has made significant and positive contributions to the project.”