We have been worked with a Surveyor out of Plano, TX on conducting this aerial mapping study with drones. We will explain the process we went through, what we were able to capture and deliver to the Surveyor and their client, how they were able to put this information to practical use, and what we learned for improvements on the next project. Here is an interactive 2D Map, 3D Map, and elevation study:
The Process:
Before we even fly, we have to get approval from the FAA for flights within restricted airspace. We filed for clearance flying up to 400′ in class B airspace. Using a DJI Phantom 4, we flew this 16.3 Acre property with an automated flight and imaging capturing process to provide more consistency. We captured 321 12 megapixel photos of the entire site. We flew at an altitude of 165′ and captured images with an 65% overlap, giving us the highest resolution models available. All of the photos are geo referenced and time stamped for proper processing. Once our field work is done, we go back to the office and start uploading all the captured photos and process our models for export.
Deliverable Exports:
Once processing is complete, we have access to digitally review 4 models and export to plug and play in Surveyor CAD programs.
2D Orthomosaic Model- We can export between a 0.4- 8 in/ pixel of resolution or quality. These are exportable in JPG or GeoTIFF formats.
Elevation Survey (as is with plants, vegetation, structures, etc.)- Exports available in GeoTIFF, JPG, Raw Elevation Values (DEM), Contour DXF (AutoCAD), Contour SHP (Shape File)
3D Model- Exported as an OBJ file, we can deliver a full 3D model of the field and what it looks like with trees, structures, etc.
Point Cloud- We can export .las and .xyz point clouds.
Exports without Plants, Vegetation, Strutures, etc.- These exports provide us with a true portrayal actual ground level elevations and studies. We can have shrubs, trees, tall grass, buildings and anything else in the way removed to put together an true ground level survey.
Practical Application:
With this project, we conducted our field work seperately. The surveyor was able to capture some control points of the centers of the man holes on the property to use as our “Ground Control Points” for properly overlaying the JPG map in their CAD program. Where they traditionally use a low quality, angled or inacurate aerial map from a satelite, we were able to provide a high resolution, true overhead map with an accuracy of roughly 7cm for this project. This provides a better, more consistent deliverable that offers a variety of different tools for the surveyor and their clients to utilize. In this study, the most useful tool for the project was the 2D Orthomosaic and here is how it was applied:
- Counting parking spaces from the map as opposed to from the field saved a lot of time. You can easily take count and document the number of parking spaces in a parking lot this way. If you get distracted in the field while counting and forget, you have to start all over.
- The use of this 2D Orthomosaic map and elevation survey saved the Surveyor roughly half the amount of time they would have spent in the field otherwise. By collecting various ground coordinates and elevations throughout the property, we were able to accurately combine both jobs to save the client money in the long run.
What We Learned and Can Improve On
While this was able to provide a lot of useful information and data to both the Surveyor and the Architect, we had some ways we needed to improve, and here is what and how:
- By capturing 8 or more GCP’s (Ground Control Points) that are visible and reviewable in the aerial map allows us to ensure proper scale, elevation, and geo referencing for the exported products.
- Capturing oblique images of the trees, structures and anything we want a true 3D model depiction of will create a more true and attractive model.
- Optimizing our flight plan to capture images from a lower elevation, with more overlap and a flying slower should allow us to get a higher resolution and more accurate map.
2D Orthomosaic with CAD Overlay:
To learn more about how Aerial Mapping can be a great added value to what you do every day, give us a call at (214) 842-6000 or click here to learn more from our website.