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Topographic surveying
- George Papastamos,

“After a first project for site planning and volume calculations, the company is now contracted to do regular follow up flights to map the work progress.”

More and more geospatial professionals are including remote sensing and aerial photography using unmanned aircraft systems (UAS) in the services they offer. The interest in using UAS is growing fast and companies see advantages over traditional photogrammetry or terrestrial surveys for many applications. Geosophy, a surveying company in Greece, is one such company.

Geosophy, owned by George Papastamos, purchased the Gatewing X100 fixed-wing UAS in early 2012 and attended a 4-day theoretic and practical training at the Gatewing office in Gent, Belgium. Their interest in the Gatewing X100 was for performing rapid aerial surveys regularly during the course of construction projects. Over the last year, Geosophy has been awarded contracts with the major road constructing companies in Greece, Macedonia, Serbia and other Balkan countries to do regular surveys. “When we arrive at a construction site for the first time, there still is some doubt on what we are doing. But as soon as the end results are presented, people are speechless” says George. Several of Geosophy’s projects are highlighted in this User Experience to summarize how their organization has benefited from incorporating UAS technology for  “After a first project for site planning and volume calculations, the company is now contracted to do regular follow up flights to map the work progress.” (George Papastamos) ! construction site monitoring and road construction surveys.

Site Construction

Geosophy has used the Gatewing X100 for construction site planning and monitoring. Two such examples of this type of use are projects from Bulgaria and Greece. The project in Greece is a gold mine in which Geosophy flew the X100 at a height of 350 meters to generate a digital surface model (DSM) to be used for excavation coordination and planning of the haul roads.

Site planning: Greece
  • Number of flights: 1
  • Flight altitude: 350 m
  • Pictures 236
  • Total area coverage: 1/5 km2
  • Acquisition time: 30 minutes
  • Processing time: 24 minutes
  • GSD: 11.7 cm/px


The project in Bulgaria was the construction of a new waste treatment facility. Geosophy flew the X100 at only 100 meters in order to generate a highly detailed orthomosaic and DSM for construction logistic coordination, calculating earthwork volumes, crane placement, and the delivery of construction materials. Geosophy continues to conduct regularly scheduled flights and provide new orthomosaics and DSMs to monitor the progress of work.

Site planning: Bulgaria
  • Number of flights: 1
  • Flight altitude: 100 m
  • Pictures 716
  • Total area coverage: 0.64 km2
  • Acquisition time: 30 minutes
  • Processing time: 38 minutes
  • GSD: 3.3 cm/px

 Image: Orthomosaic of construction site in Bulgaria

Road Construction 

Corridor/alignment construction are another type of project where Geosophy have utilized their X100. As with site construction, work progress monitoring and volume calculations are needed on a regularly scheduled basis. In many cases, construction progress must be reported to local agencies or authorities. The projects included illustrate how the X100 was used throughout the different phases of a construction project - from initial planning to regular progress monitoring and finally delivering as-built reports and maps of the newly built roads. 

The road project in Macedonia was mapped every two months during construction to evaluate progress. The client requested that Geosophy provide both an orthomosaic and digital surface model with +/-15 centimeter accuracy. In addition to these common deliverables, the client also asked for a 3D visualization that could be shown to the local government agency. The corridor was determined to be too long to be effectively surveyed with a traditional survey crew yet too small to justify being covered with a traditional airborne system, hence the choice to use the Gatewing X100. The project conditions were challenging with the rough and mountainous terrain, limited take-off and landing areas with hard gravel to land on. The project was split into 3 flights, each flown at 400 meters. The total time to complete a survey of the entire corridor, including flight planning, performing flights, and generating deliverables took the Geosophy team 3 days. They figure it would have taken them twice as long just to acquire the data with a terrestrial survey crew and would have had a higher cost.

Corridor mapping: Macedonia

  • Number of flights: 3
  • Flight altitude: 400 m
  • Pictures 890
  • Total area coverage: 16 km trajectory
  • Acquisition time: 30 minutes/flight
  • Processing time: 90 minutes 

Video: Flights June & August

Video: Flights October

Corridor mapping: Macedonia
  • Number of flights: 7
  • Flight altitude: 400 m
  • Pictures 1355
  • Total area coverage: 28 km trajectory
  • Acquisition time: 35 minutes/flight
  • Processing time: 182 minutes

Video: Work planning flight in Macedonia

Corridor mapping: Serbia
  • Number of flights: 1
  • Flight altitude: 400 m
  • Pictures: 384
  • Total area coverage: 9 km trajectory
  • Acquisition time: 30 minutes/flight
  • Processing time: 41 minutes


What's next?

After their first year using an unmanned aircraft solution from Trimble, the Geosophy team has experienced numerous advantages on the projects where they have utilized it. With more than fifty flights in a variety of projects, they are convinced that UAS technology will be a valuable tool for them going forward. Geosophy has decided to upgrade to the new Trimble UX5 Aerial Imaging Solution that was released in July 2013. “The X100 was chosen since it was a turnkey solution at that time but the UX5 system will allow us to be even more efficient since the smaller landing area, improved robustness and increased area coverage per flight” says Papastamos.

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