Lidar technology for growing cities and economies
South Africa is starting to see great opportunities for economic growth. Data from the United Nations shows that the country’s population is set to increase by around 11-million to 65,5-million people by 2050. New approaches are therefore needed to ensure that the country’s infrastructure can not only cope with the increase, but also supports the nation’s ability to be at the forefront of innovation.
The South African government predicted that 80% of the population will be based in urban areas by 2050. With this will come a greater need to ensure that cities are capable of providing services that truly fit the needs of its citizens. Smart cities are emerging across the globe to increase efficiency of services, and to improve the lives of residents.
Fig. 1: Urban mapping showing vectors and height clearances.
A smart city is defined by its ability to apply advanced information technology, analytics and systems to manage a city’s assets. The aim of a smart city is to improve the accessibility and efficiency of services, which not only enhance stakeholders’ lives, but also drive economic improvements within a specific urban area.
Advancements in technology are taking place across all areas of urban infrastructure, including intelligent transportation systems, digitally integrated public services and data-driven utility supplies. Smart city methodologies are therefore seen as a way of easing the burden placed on services by our ever-growing population, and assist in creating a sustainable economic future. Integrating these technologies has its challenges, as much of the city’s current infrastructure may remain while the foundations for a digital future are laid. A thorough analysis must therefore be conducted of the current topographical landscape to ensure that any plans are not only future proof, but also take into account current restrictions and limitations.
Any large infrastructure project is usually made up of four stages – design, planning, construction and maintenance. Smart cities require a fifth element to be considered – data collection and interpretation. Light detection and ranging (lidar) is emerging as the secret weapon of the city planner and civil engineering surveyor, as it allows data to be collected at the beginning of any project, using time-series to monitor changes over time. Lidar works in a similar way to sonar or radar, using light waves instead of sound or radio waves to measure the distance between two points. All these technologies rely on the echoes, or return of waves to calculate distance. Only lidar is capable of collecting the millions of points, or returns needed to create an accurate 3D model, and is accurate down to millimetres.
Fig. 2: Point cloud from a vehicle mounted mapping system.
Lidar data is becoming increasingly vital in urban planning because of its value in applications such as building information modelling (BIM) and asset management, in addition to the ability to track and monitor changes in the landscape. Once captured, the data collected can be utilised for multiple purposes wherever there is a need for visualisation in three dimensions. Applications include full transportation strategies from bridge clearances to route optimisation for self-drive vehicles, all the way through to flood plain mapping and coastal erosion. Data acquisition is the most labour intensive process of any surveying project, with single point collection systems known as total stations, or terrestrial laser scanning systems, being the traditional tool of choice for accurate measurements. These methods require the system to be in a fixed position for each measurement to be taken, often on a tripod.
Advancements in technology now mean that mobile lidar systems are equally, if not more accurate, with the added benefit of expedited data acquisition. Imagine the time it would take to scan the city of Johannesburg, at over 1645 km², even with a high-performance scanner that is capable of collecting data up to 800 m away. Many repeated set ups would be needed, with road closures and other disruptions inevitable to cover a whole city grid.
Flexible mobile systems, such as the Robin and StreetMapper, allow for a scanner to be mounted on a car, bus or drone which enables data from large areas to be acquired quickly and continuously without interruptions to services and with less risk to operatives. The Robin +Slam takes this even further, with the ability to create a seamless dataset indoors, even with limited GNSS coverage, through to outdoors, without having to stop. As the system can also be mounted to a backpack, it means that hard to reach urban areas can be covered in great detail. From the likes of basement levels and tunnels, to forests and parks, one system can now be used to map an entire city.
Fig. 3: Lidar data of a city grid.
Mobile mapping systems provide a very rich dataset, a point cloud, made up of millions of returns, to allow even the smallest of features to be captured for future analysis. This level of detail takes a lidar point cloud into the realms of big data – huge amounts of information, which can be studied on many different levels, to reveal patterns and in-depth insights, especially in an urban environment. The importance lies in how this data is extracted and used, as the initial application can often provide different levels of detail relevant in other projects such as monitoring and maintaining a city’s assets.
The management of big data is crucial when it comes to incorporating smart city methodologies. Advances in lidar technology has also meant great leaps have been made in the development of processing software, which allows operators to visualise and analyse the millions of points collected by a mobile mapping system. Terrasolid and Orbit GT are two such platforms that assist with the interpretation of datasets, which often amount to terabytes of information. This allows for manipulation and extraction of information down to individual features, to assist with the cataloguing of assets from traffic signals to street furniture.
Many cities and countries across the world are collecting lidar for a variety of purposes. Washington State in the US recently released data of around 27% of the capital, with the aim of allowing government agencies and relief operators to collaborate on the analysis of geohazards, such as landslips. This allowed for planned preventative maintenance and emergency response strategies to be successfully co-ordinated between the two outlets.
The UK’s Environment Agency has spent nearly two decades using laser scanning systems to model and track changes on the country’s coasts. They recently made 17 years’ worth of lidar data available on an Open Government Licence to allow it to be used for any purpose, including education and commerce. The datasets amount to 11 TB of data and cover approximately 72% of the country’s landscape.
The complexity and level of detail contained within lidar data means that it is suitable for a broader strategy, which realises on the potential of combined intelligence. The benefits of smart cities and the associated data collected are often lost on individual citizens. It can often seem as if technology is being integrated simply for the sake of it, without obvious meaningful benefits. In reality, the advantages can be seen in many global cities and increasingly across the African continent.
Fig. 4: Point cloud generated by a mobile mapping system.
Lidar data can be used by various departments for different applications, including smart mobility and transportation strategies, to utilities and water and waste management. More importantly, it can be used to create a layered, digital by default, city plan, where it is possible to visualise and implement change in real-time. This premise relies on collaboration between city leaders and influencers, to decide on how this critical information can best be used to benefit the community and local economy.
In 2014, the city of Durban received a grant from IBM to assist with economic development plans in the eThekwini Municipality. In little over two years, water and sanitation has been transformed in many of the city’s 500 townships, and work has started to transform the docklands into the country’s first smart port. In 2016, the city also put out a tender for an aerial lidar survey, which would provide accurate elevation data across the whole community. The resulting maps can be used to upgrade public services, including to improve transportation links, as well as to monitor the area for environmental change. This will assist in the creation of emergency response strategies for floods, landslides and earthquakes.
There is also a commitment towards engaging Durban’s youth by providing training and events that actively encourage technological innovation. Data being used by city planners to assess powerlines for example, can also be used to create interactive, immersive experiences, which allow young people to play an active part in the development of their community.
Meanwhile, in Scotland, a government grant has allowed lidar data to be used to encourage children to study engineering subjects. Point clouds created for other projects are also being used to create augmented reality games and real-time interactive models for virtual reality headsets, which help children to understand their environment in a different way.
In summary, over 80% of the world’s GDP is generated in cities. The rapid urbanisation we are starting to see requires a new approach to information gathering so that our growing communities have a robust and futureproof infrastructure. The possibilities of lidar data are so great that the same information has scope to be used across many different applications, to improve life for us all. The ultimate aim would be to have detailed, searchable 3D maps of all cities across the world, which are accessible to both government agencies and the general public. Best practice and innovations could then be compared on a global level, to help ensure that our future cities integrate technology to its advantage.
Contact Matthew Bester, 3D Laser Mapping, Tel 012 683-8766, matthew.bester@3dlasermapping.com
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