We produce the digital twin of the slope: point cloud, surface model, sections, block inventory and discontinuity orientations from drone photogrammetry and terrestrial scanning. The design is built on this survey.
In a slope project, the most expensive mistake is using an unmeasured number as if it had been measured. The slope height is read from a map, the gradient is estimated by eye, the block size is noted as "about one metre". Then the barrier class is built on these numbers. Measurement is the first link of this chain; this is where we start.
Two methods, one output
Aerial photogrammetry. Images are taken with a drone along a planned flight line with ground control points. It gives coverage quickly on large slopes and produces an orthophoto, a dense point cloud and a digital surface model.
Terrestrial scanning and close-range photogrammetry. Used on steep rock faces, overhanging sections and pockets not visible from the air. It completes the surfaces left in shadow by aerial imaging.
The two are merged in the same coordinate system. Which part was measured with which method is written in the delivery file.
What the survey produces
| Product | What it is for |
|---|---|
| Point cloud and surface model | The basis of the whole design; volume, area and distance are read from it |
| Orthophoto | A scaled aerial image; cracks, outcrops and vegetation boundaries are marked on it |
| Contours and sections | Sections along the fall line; barrier line, anchor plan and quantities |
| Block size inventory | Mass of the design block; the energy class choice comes from this number |
| Discontinuity orientations | Input to sliding, toppling and wedge analysis |
| Difference between two flights | Deformation monitoring, scaling quantities and progress payments |
The survey output goes straight into the design: the terrain model for the trajectory analysis, the slope geometry for the anchor calculation and the layout of the barrier line come from the same file. For a rough order-of-magnitude reading there is the trajectory tool (Turkish); the final design is made with the measured model.
How accurate
Accuracy is not a single number; it depends on the number and distribution of ground control points, the flight height, the surface texture and the imaging geometry. In every job the measured accuracy is reported together with the check point residuals. Accuracy that is not reported is not accuracy.
We state two limits from the start. Vegetation hides the ground; the surface under trees is not seen by photogrammetry, and those areas are either filtered out or counted as unmeasured. Discontinuity orientation read from the surface degrades as resolution drops; a joint measurement taken from a decimated model does not replace a compass measurement on site, it complements it.
Delivery
Point cloud and surface model, orthophoto, sections, survey record and accuracy report. The record states the flight date, the coordinate system used, the ground control points, and which values were measured and which are assumptions.
If your slope needs to be measured, request a survey; a location and a photo taken from a distance are enough (contact).