(Editor’s Note: This is the first of a two-part series on spatial technology.)
Innovation in spatial technology is transforming some of the world’s most important economic sectors. For example, the McKinsey Global
Institute estimates that the world will need to spend $57 trillion on infrastructure through 2030 to keep up with global GDP growth. To meet the world’s future infrastructure needs, construction needs to be reinvented through a productivity revolution. Two key spatial technologies, surveying, frequently called reality capture, and building information modeling (BIM) are key to this transformation of construction.
In the 1970s, major aerospace companies pioneered computer-aided 3D modeling and experimented with mixed reality. This transformed the way aircraft were designed and built, and helped to improve sector productivity by up to 10 times. The first 3D technology that has had significant penetration in the construction sector is building information modeling. Many studies have documented the benefits of BIM, including 20% lower construction costs, no or reduced rework, and savings on material costs. A number of governments including the United States, Britain, Singapore, France, Russia, Finland, and others have or are mandating BIM for public construction projects. Next-generation 5D BIM is a five-dimensional representation of the physical and functional characteristics of a project. In addition to the 3D geometry and database of information, it includes a project schedule (time) and record the impact of changes on project costs and scheduling. BIM technology is further enhanced through mixed reality technology. In a mixed reality environment, stakeholders in a design project can visualize, interact, and make changes to
a design before the design is built in an intuitive, immersive environment.
New reality capture technologies that integrate high-definition photography (PhoDAR), 3D laser scanning (LiDAR), geographic information systems (GIS), and unmanned-aerial-vehicle (UAV) technology are not only dramatically improving accuracy and efficiency, but also transforming the construction process. Laser scanning technology is much faster than conventional technologies and provides high-quality 3D point clouds that can be integrated with BIM. LiDAR, in conjunction with ground penetrating radar, can generate aboveground and underground 3D images of project sites. Point clouds are generated by both laser-scanners and PhoDAR software that generates them from digital images. But point clouds are just too big and have too little intelligence for many applications. 3D meshes, which are generated from point clouds by a process of triangulation, are compact and easier to manipulate and are replacing point clouds for many applications. Geographic information systems enable maps, 3D point clouds and images, meshes and survey points to be integrated. This information can then be uploaded to other analytical and visualization systems for use in project planning and construction.
Modern reality capture technology is more accessible than ever before because costs have come down substantially. The first handheld 3D scanner was released by Dot Product in 2012, based on technology introduced by the Microsoft Xbox 360 Kinect. Since then, at least five more handheld 3D scanners have been released by other vendors. Leica Geosystems has just released a professional imaging scanner weighing one kilogram that lists for only $16,000. It has a precision of millimeters and a range of 60 meters, and is able to complete a 360 degree scan in less than three minutes. Professional handheld 3D scanners with a range of about three meters are available for $3,000 to $5,000, and a 3D scanner that can be mounted on an iPad is available for only $400. Mantis Vision, who is working with the Google Tango project to make 3D scanning available on an android tablet, promises to make its technology universally available (being able to scan an object, share the 3D model online, and send it to a 3D printer) from a smartphone.
Automating the classification of meshes, also known as feature extraction, remains a challenge, but even industry-standard software such as Trimble RealWorks (TRW) can identify walls, floors and ceilings inside buildings and ground, buildings, vegetation, and curbs and gutters outside. The latest version of TRW 10.3 can even resolve power lines, which is critical for automating vegetation management for transmission lines. Machine learning is being applied to the problem by Bentley and Microsoft and it is likely that in the near future it will be possible to automatically classify most 3D scanned imagery.
A new groundbreaking laser scanner, the SPL100, which relies on single photon laser scanning, has recently been released by Leica. A single photon laser scanner is a new technology that differs from the current mainstream laser scanners in that it can detect weaker reflected light. It can collect six million points per second, which means that planes conducting overflights can fly higher and still collect 20- 30 points per square meter, which is 10 times more efficient than conventional laser sensors for large scale mapping.
Since the introduction of satellite-based global navigation systems – GPS (U.S.) and GLONASS (Russia) – in 1995, navigation out-of-doors has been revolutionized. But indoor navigation has remained a major challenge. The development of microelectromechanical systems (MEMS) in the 1980s and 1990s has made possible the mass production of micro inertial measurement units (IMU) comprised of a combination of accelerometers, gyroscopes, and magnetometers. These have enabled the smart phone which contains a range of sensors, typically an accelerometer, thermometer, gyroscope, pressure sensor, humidity sensor, light sensor, location sensor (GPS) and a magnetometer.
A key technical advance that took advantage of these microsensors is fast structure-from-motion (SfM) algorithms which were first applied in the development of autonomous vehicles, allowing them to navigate without a GPS. In 2012, the simultaneous localization and mapping (SLAM) algorithm, which solved the problem of constructing a map of an unknown environment and navigating with it, was developed by Australia’s CSIRO. This made it possible to accurately track the location of a person inside a building or in an obstructed environment such as a city. The technology has been successfully applied to indoor mapping and is available in the form of backpacks loaded with sensors and computers from Indoor Reality and Leica Geosystems (Pegasus Backpack). Indoor Reality developed technology that can accurately track the location and orientation (six degrees of freedom) of a backpack containing LiDAR and other sensors as the operator walks through a building going into rooms, halls, up and down stairs and into other human accessible spaces.
Hovermap is a CSIRO application that provides a SLAM-based 3D LiDAR mapping payload for small UAVs. It provides omnidirectional collision avoidance, advanced autonomy, and the ability to operate in GPS-denied areas. SLAM makes it possible for the drone to navigate in complex geometric environments without GPS, while the onboard autonomy makes possible mission execution without human intervention. Some applications include construction site mapping (inside buildings and outside), underground mine mapping, and transmission line mapping and monitoring.
The commercial operation of UAVs is allowed in most jurisdictions, including the United States. However, the Federal Aviation Authority (FAA) only permits UAV flights with visual line of sight (VLOS) rules. This is changing with far-reaching implications. Last year, three organizations were granted FAA permits which allowed them to fly the first beyond visual line of sight (BVLOS) flights in the U.S. The next major commercial development of UAVs will likely be data collection and geospatial analytical applications for transmission lines and large-scale construction projects.
Earth observation satellites are providing more frequent high resolution imaging of the earth that has many applications. The Worldview-4 earth observation has just been launched, which enables the DigitalGlobe constellation of satellites to photograph any spot on Earth more than four times per day at a resolution of 30 cm (about a foot). In February, Planet Labs launched 88 Dove satellites to orbit. Planet Labs now operates 144 satellites in low Earth orbit. Each of the latest satellites is capable of collecting more than two million km² per day, which means that the entire constellation has the capability to image all of Earth’s landmass every day. Applications include energy, mining, finance, and critical
infrastructure for power or transport.
This has been an introduction to some of the technologies that are transforming construction. In the next issue, some of the most interesting applications of these technologies will be discussed.
Geoff Zeiss has more than 20 years of experience in the geospatial software industry and 15 years of experience developing enterprise geospatial solutions for the utilities, communications, and public works industries. He can be reached at Geoff.zeiss@
betweenthepoles.info.
