Drone Based Land Surveying and Engineering
In 2016 D.L. Howell & Associates and HowellKline Surveying saw that the use of UAVs in the field would only increase. We knew it was essential to add this tool to our engineering and surveying toolbox. We started with one drone pilot and now have five drone pilots between the engineering and surveying companies.
Becoming a Drone Pilot
Commercial drone pilots are required to have an FAA part 107 license. In order to obtain their FAA certified drone license, students must take and pass a test provided by the Federal Aviation Administration (FAA).
The Use of Drones in Surveying
The Unmanned Aerial System (UAS) is a remotely controlled quad-copter equipped with a high resolution camera. The high resolution pictures can be digitally stitched together to create what is known as a digital ortho-photograph. An ortho-photograph is a photo that has any distortion removed, thereby allowing accurate measurements to be taken between points in the photo. Three-dimensional point clouds can also be generated from the photographs, allowing for measurements in 3D as well.
Drones work as a tool in civil engineering and surveying to decrease the amount of time that it takes us to get survey data or imagery of the job site. Using a drone has reduced some of our data acquisition time to about 25% of what it would typically take.
The process of using drones for a project is simple. Depending on the size of the job site and scope of the project, we will use our UAVs to gather site imagery, similar to a Google map, but much more accurate. We are then able to convert that imagery to AutoCAD usable files.
A project that would traditionally take five days of hand field surveying to complete now takes just one day with the use of drones.
UAS / Drone Use for Surveying and Engineering:
- High-Resolution Aerial Photography of the project site
- ALTA Surveys
- Geo-referenced Tiff Image of the project site in world space
- Area Calculations Using Photogrammetry
- Topsoil Stockpile Dirt Measurements
- Basin Volume Measurements
- Sports Field Elevation
- Impervious Coverage Calculations
- Distance Measurements
- Asset Accounting such as cars or trees
High Resolution Imagery
Most engineering and surveying companies use Google maps to look up the locations of sites, and while this is a valuable resource, the imagery is not of a high enough resolution to base any work. The satellite image could be so outdated that it does not show what is currently on the site. Drones offer same day ortho mosaic images at a very high resolution.
The Flight Process
Howell Kline can control the resolution and accuracy of the final ortho mosaic image. The process of creating and executing a flight plan is as follows:
- First, we take a look at the site using our drone processing software and outline the area of the job site we wish to capture.
- Next, we design a UAV flight plan and set variables such as the drone flight height and image overlap to increase the accuracy of the final image.
- The UAV follows the flight plan and collects data and imagery.
- We process the data and imagery and use it to enhance your project. We can create various types of exports, such as flat, top-down ortho mosaic images that can range in accuracy from .5 inches per pixel to 20 inches per pixel. We can also get elevation imagery, which is a color-based image map that shows the elevation changes on the site.
Site Elevation Information
Another aerial drone image available is elevation imagery, which is a color-based image map that shows the elevation changes on the site. In the image below, you can see the different colors on the site that show how the elevation changes. The darker and lighter blue areas show the road and ground elevations while the red and green areas show trees and buildings. These elevations can be tweaked to show ground areas so that we can get an accurate idea of how the ground elevation changes over the entire site.