The rapidly growing infrastructure tends to leave behind a number of failures, that are usually fixed after a bigger disaster. The same situation happens when building the roads with slopes aside.

To prevent such mishaps, photogrammetric surveying can help determining at least one major factor with minimum effort – slope angle or the slope height. Though, in many cases one factor is not enough – knowing all the angles can give you a better perspective, but it cannot solve the problem precisely.

In this use case, we are going to overview the problematic areas around a relatively newly constructed ring road. To evaluate the both slopes at the newly built detour we used the DJI Phantom 4 Pro.

 

Orthographic views project at a right angle to the data plane. An orthophoto, orthophotograph or orthoimage is an aerial photograph or image geometrically corrected ("orthorectified") such that the scale is uniform. Can be used to measure true distances, because it is an accurate representation of the Earth's surface, having been adjusted for topographic relief, lens distortion, and camera tilt.
High Quality Orthophoto

 

High quality “orthophoto” enables seeing the 3D bird’s eye view in the computers screen and already gives an idea about the state of the slope and its surface type. In this case we observe grassy newly made embankments.

 

 

Digital elevation model provides detailed terrain information. DEM layer is useful for quick and unlimited visualization of surface relief and accurate object analysis.
Orthographic Shading of the DEM

 

The “orthophotographic shading” gives user an opportunity to immediately notice the beginnings of shallow slope failure in two particular areas, which is difficult to spot with the regular DEM.

 

 

These examples are the obvious warning signs that slope might be unstable and prone to shallow, rainfall or vibration induced failures.

 

 

Profile” feature can show the angle, distance, height and other important numbers. This feature can be made everywhere just by drawing a line in the selected place.

In the pictures below using the “profile” feature we will estimate the slope  and the landslide height.

 

If we put the measures in one table we easily can see the tendency of the landslide to appear nearly at the same height of 4,2 – 4,4m. As the slope angle does not vary so much and stays around 31 degree, we can clearly see that the appropriate slope height would be not higher than 4,4m

 

To calculate the volume of the ground that needs to be excavated in order to lower the slope, we will use the smart polygon feature.  It enables to measure the slope surface by selecting the desired place.

 

 

First we need to mark the required height of 4,4m. This line will be the lowest point of the place. To optimize the ground excavation process (must be gradient, not terraced) we will select the points that are further from the slope and using “level by averaging” feature will flatten the surface.

 

 

In order to calculate the volume, we have to compare the initial project with the entire slope volume with simulated project when the slope is lowered. Object comparison in time feature clearly shows that this particular section needs to take off 1054 m³ need to be excavated.

 

Summary

With the help of the drone and photogrammetric software, one can inspect, measure and prevent costly slope failures with no extra investment.

For the monitoring efficiency, it’s important to get all the updated information. The functionality and the latest features of Pixprocessing software lets to evaluate the risks (angulation and height) and simulation tools are useful for the workflow calculation. One of the biggest advantages – it doesn’t require to physically drive and measure all the splits. We only need to make a photo set of the location and process it to the software.

Find more info at:  https://pixprocessing.com/pixprocessing/