By seamlessly integrating two powerful data sources, you can achieve a comprehensive understanding of your worksite's progress. Drone surveys provide a high-level, aerial perspective by capturing data from the sky, while DirtMate complements this by gathering real-time data directly from machines on the ground. This unified approach delivers accurate worksite data, offering clear insights into production efficiency that are easy to view, share, and act upon.
How drone flights and DirtMate surfaces interact
A new drone surface provides an updated source of “ground truth.” This update is made to the site surface at the time of the flight, resetting the DirtMate surfaces.
Drone Flight Frequency
Flying a drone frequently on a site that employs DirtMate is recommended to provide an accurate baseline for DirtMate data. Installing DirtMates on all machines on site is the best practice. However, that may not be feasible for some sites, such as those that are importing material. A drone flight will ensure that any work performed by machines that do not have DirtMate installed is still reported.
For best results, we recommend flying sites with DirtMates at least weekly. If you can’t fly weekly, you should fly a drone survey at least once a month.
Volume inconsistencies at time of flight
DirtMate data is live; therefore, adding a new drone flight to the site can cause surface inconsistencies. These inconsistencies are seen on the surface as a larger volume difference during the time of flight. This is due to a couple of factors: the accuracy of the drone surface and work being completed during the drone flight.
Drone surface accuracy
Drone surfaces have an accuracy of ~3cm on a per point basis. Due to the process of volume calculations, this can cause a 0.2-0.3 foot (6-10 cm) error on drone survey comparisons, even on areas that haven’t changed. The effect of this can be significant over large areas. For example, if measurements are made between two drone surveys, the error over a 330 ft x 330 ft (100 m x 100 m) area could be:
0.2 ft to 0.3 ft x (330 ft x 330 ft) = 21,780 - 32,670 ft3 or 807- 1,210 yd3 |
| 0.06 m to 0.10 m x (100 m x 100 m) = 600 - 1,000 m3 |
We discuss this in more detail in the Accuracy of Photogrammetry and impact on volume measurements white paper. This potential inaccuracy can cause the DirtMate site to register a significant change in cut and fill, which in turn impacts both the heatmap and volumes. The best way to avoid volume discrepancies due to an uploaded drone flight is to limit the areas you’re calculating volumes for; e.g., just to a specific working area, or a boundary to design.
Work Completed during the drone flight
Drone flights are not instantaneous, and work can be done during flight. Currently, Propeller will register the drone flight at the time of the earliest image. Because the drone flight is represented as a single point in time, any work captured by DirtMates during the flight will be registered as a single cut and fill value of the opposite sign at the earliest photo time. After the last photo timestamp, the DirtMate data will no longer conflict with data from the drone flight, and the DirtMates will continue updating the sites with the latest surfaces. With this in mind, please rely on the daily volumes for those days when a drone flight occurred, as it may take up to 3 hours for the volumes to stabilize following a drone flight.
I still can't do it!
We wrote these articles to equip you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.
If you're stuck, the Propeller Site Support team may be able to help. You can contact our support team by emailing sitesupport@propelleraero.com.au.
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