Tonon USA uses digital photogrammetry to create three-dimensional models of slopes, whether natural or man-made, such as surface excavations, trenches, quarry faces, large foundations (dams, bridges, buildings), stockpiles, and tailings.

When the site morphology and access prevent an efficient layout of camera stations on the ground, Tonon USA uses boats, its own Unmanned Aerial Vehicles (UAV) or other aircraft to take the photographs of otherwise inaccessible slopes. A specific feature of Tonon USA UAV is that there is no need to place targets on the slope, while still achieving a global accuracy of 1 cm (2/5 in): this is a major advantage for dangerous and/or inaccessible slopes. This simple sentence is the result of hundreds of hours of R&D, and substantial monetary investment.


To illustrate, Tonon USA was called to monitor a slope that is the source of continuous and dangerous rockfalls onto a major highway, with major damage to bridge decks.

Installing camera stations on the opposite slope (1 km away from the vertical face) would not have been practical and would have created shadows because of the concave nature of the slope.

Tonon USA determined the camera locations and developed the helicopter guidance system to achieve the requested 2.5 cm (1 in) accuracy for the entire slope, which is 500 m (1,500 ft) high, and 600 m (1,800 ft) wide. The figures below show a portion of this 3-D model of the rock slope.

These three-dimensional models textured with high resolution pictures may be used to (click on each item for details):

  1. Carry out a detailed structural mapping (fracture orientation, trace length, spacing) and document lithologies.
  2. Identification and measurement of unstable blocks
  3. Reconstruct the entire rock/soil mass exposed during different construction stages.
  4. Document in 3-D the construction stages with associated excavation/placement volumes.
  5. Monitor displacements.
  6. Obtain the three-dimensional geo-referenced as-built model of a project textured with high resolution pictures; a baseline for future inspections (new construction) or documentation of defects and change of defects over time (existing structures).



Phone: +1-512-200-3051


2028 E Ben White BLVD #240-2660 - Austin, TX 78741