To support local action, the European Union has promoted the Covenant of Mayors (CoM), a movement designed to endorse and support the efforts deployed by local authorities to implement sustainable energy policies through the submission of Sustainable Energy Action Plans (SEAP).
Rational energy consumption
At the end of 2011 an ESCO (Energy Service Company) composed by several CoM members enlisted the services of Gemmlab, a firm based in the Padua, Italy area, to help put its SEAP into practice through a census of the street lighting systems in selected Italian municipalities. Gemmlab was chosen because of its expertise in the development of land management solutions and the creation of geospatial databases through the acquisition of spatial data via topographical surveys. The effort would prove useful for the redevelopment of the entire system, with the aim of better managing energy consumption and reducing light pollution.
“Practically speaking, for me and my staff, the challenge was to collect an enormous amount of spatial data in a relatively short time period,” said Giovanni Manta, Gemmlab’s owner. “This work took us to towns of varying population and landscape spread throughout the Italian peninsula.”
It would not be an easy task. Manta prepared a preliminary study to identify the best strategy, estimating man-hours and the number of teams needed to assess the topography of the area.
When the census began in early 2012, Gemmlab allocated four of the company’s 25 Trimble Juno 3D handhelds to the project. The teams in the field, composed of four operators, manually surveyed the street lights, capturing GPS coordinates or marking a street light directly on the map when urban canyons rendered GPS signals unavailable.
“The work proceeded surely but slowly,” said Manta. “But I was seeking out new ways to speed up the process, reduce costs and improve the accuracy of data collection and utilization. In addition, due to safety concerns, I sought to reduce the number of operators out on the street.”
A New Challenge
In July 2013, in an effort to improve its surveying process and take part in a viable commercial venture, Gemmlab and its partner company Crisel acquired the newly-released Trimble MX2, a vehicle-mounted spatial imaging system that combines high resolution laser scanning with precise positioning to collect georeferenced point clouds. In early 2014 Gemmlab rolled out its own mobile surveying system: a vehicle equipped with the Trimble MX2, a LadyBug 360° video camera for digital imagery and Trimble AP20 GNSS-Inertial System to sync data to the route. This technology combination would allow Gemmlab to bypass much the manual surveying of the street lights.
In operation since April 2014, Gemmlab’s system has provided extraordinary benefits and allows for the surveying to be carried out directly along the streets. In the event that the team of two operators (reduced from four) encounters an inaccessible road, they can still perform a manual survey. In general, however, the surveys can be performed from the vehicle: the team can drive through the narrow streets and alleys of medieval towns that are otherwise inaccessible with vans or similar vehicles.
The operators’ tasks are divided as follows: one person drives the vehicle and sets the pace of the survey with the help of an application developed by Gemmlab. The second operator deals with data acquisition, monitors the instruments and verifies the efficiency of the acquisition process.
During data acquisition, the Trimble MX2 acquires 360° point clouds of the surrounding scene. At the same time, the video camera collects high-resolution imagery of the scene, providing additional information for data analysis. The information is stored and pre-processed with a laptop computer located inside the vehicle.
Once in the office, Gemmlab’s staff uses Trimble POSPac software to improve GPS accuracy of the vehicle’s trajectory using RINEX data from the regional GNSS network. They then convert the information into data ready for feature extraction. The data is processed through the Trimble Trident Imaging Hub, which enables information classification and extraction from digital imagery and point clouds.
Gemmlab’s GIS team then produces 3D shapefiles ready to be unified into a single geodatabase. The spatial features of the database are necessary to locate and access each and every street light and its associated attributes (address, road width, distance between each light pole, pole heights, etc.), which play an important supporting role within CAD and GIS environments.
According to Manta, the greatest practical benefit of the system comes from the processing capabilities of the POSPac software suite, which he says allows the team to reach the data extraction phase quickly. The precision of data deliverables – about 8 cm (0.3 ft) – is well within the range specified by the customer.
Results Beyond Expectations
The use of the laser scanner with digital imagery and GPS, as well as the ability to create GIS and CAD data deliverables, is a good example of the increasing role technology integration. Manta was able to find optimal solutions for a task that once seemed impossible. The integrated approach increases overall throughput by avoiding manual data entry in the office and provides additional opportunities for utilizing the field data. For example, it is possible to use the database as a road graph layer or represent graphically the terrain and its features.
The results of Manta’s approach are clear. During the first phase - carried out in 2012-2013 for about 14 months of actual work - the teams manually surveyed with handheld devices 36,233 street lights in 33 municipalities. The integrated survey solution doubled that daily productivity. By early 2014 the new survey approach involved five towns: in about 35 days of work between April and June the operators covered an average of 110 km per day, collected 7,441 points and approximately 575 Gb of data. The work represents an increase of 20 percent over the estimates of 5,980 points made by the municipalities. In addition to bringing higher precision, the solution provides the ability to retroactively verify data as well as increasing the safety of the operators in the field. Giovanni Manta and his team expect to survey in just seven months the same number of points that once took more than a year to complete.
Gemmlab keeps its high-tech vehicle very busy surveying the narrow streets of Italian towns. “The vehicle demands attention,” said Manta. “Passers-by often stop to speak with the operators out of interest in what is going on. Some municipalities have also considered the possibility of using the system for dedicated marketing purposes.”
Through a combination of strategic planning and a unique technological vision, Giovanni Manta found a way to save time and reduce costs while making gains in accuracy and safety. The census will provide authorities with data deliverables that will help the implementation of sustainable policies at a local level and will eventually foster European Union’s commitment to a 20 percent reduction of CO2 emissions by 2020.
Fulvio Bernardini is a technical writer, translator and editor based in Rome, Italy. His work focuses on the geospatial field. He also writes about cartographic communication, sustainable development and music.