Drones are a great resource for effectively and efficiently capturing direct overhead images at a high resolution to process detailed aerial maps on relatively smaller projects.
Today’s advancements in accurately located imaging and post processing capabilities allow for highly accurate map deliverables, routinely helping land surveyors make their jobs easier and cutting down on time.
This article reviews the advancements in technology, post processing capabilities, and where this new resource proves to be a benefit to the land surveying industry.
Leaning on new technology to do the work
Technological advancements are giving us up to about 40 minute flight times for rotor wing and up to 3 hours on fixed wing drones. Many drones vary in size and payload capabilities, but we have the ability to capture up to 42mp still shots in a vertical format — giving you amazingly clear visual images.
These images are captured systematically and are all GPS located. Some UAV systems come equipped with RTK systems that correlate precise GPS location data to the images, helping to process highly accurate aerial maps without the need for ground control point documentation.
How quickly the images can be captured depends on the elevation and image overlap.
Post processing to get the accurate map you were expecting
Once the field data is collected, there are various ways to post process a stitched map, often varying in the level of accuracy delivered.
Even though the file sizes can be quite large depending on the size of the property, we can process a resolution of as good as .3″/ pixel of the stitched map. Lower resolution images can be processed to help with upload time into CAD programs.
If processing maps using ground control points, or proper RTK systems, map accuracy can be as good as .6″ of horizontal and 1″ of vertical relative accuracy.
Without these methods, the map can be processed often within about a 2′ level of relative accuracy and many CAD programs today provide a way to manipulate the image to stretch portions based on points and visual references to achieve a similar level of accuracy as if processing was completed with ground control points or the use of an RTK system.
Benefits: the goal is to save both time and money
Today, these high resolution and highly accurate aerial maps provide unique value in ways other methods have not. The whole idea is to increase efficiency and cut down on costs.
This is most valuable on commercial and multiple acre properties. Surveyors are finding this resource a better tool for counting parking spaces rather than walking and counting in the field.
Once the map is accurately overlaid, you can then determine corners of buildings and other structures with ease. You can have a good, high resolution, and accurate visual representation of spray painted points and references of other objects on the property. It can be very helpful with determining elevations in creeks or slews that are otherwise very time consuming and difficult to survey.
When the trees are bare in the winter, we can usually get a pretty good image including the ground of wooded areas. Once you learn the resource and how it can be applied practically, you can probably thing of other ways it provides a tangible value. Even though using drones might seem expensive, the end game is to save you time and money.
The numbers may not work out properly on every project, but when they do, its worth every penny spent.
Need more insight regarding the use of aerial mapping with drones?
To learn more about aerial mapping or discuss a project that could be a good fit, give us a call today at (214) 842-6000!