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Aerial Mapping

The Truth about Drones in Mapping and Surveying

Below is an excerpt from an excellent article written by Bill McNeil/Advisor and Colin Snow, CEO and Founder of Skylogic Research. It shows how drones have been used successfully in surveying and mapping thus far and outlines the lessons learned. It goes on to discuss the opportunities and challenges for GIS professionals, reviews competitive and traditional approaches offered by incumbent technology, and discusses what’s next for drones in this sector. The full text of the report can be seen HERE

Image Credit: Future Aerial

Image Credit: Future Aerial

“Drones are going to have a major impact on the surveying and mapping industry, but perhaps to a lesser degree on traditional surveyors.  As mentioned earlier, the Department of Labor is forecasting a 2% drop in the number of surveyors from 2014 to 2024.  On the other hand, the Labor Department is projecting 29% growth for the photogrammetry category.  This means more and more photogrammetrists will do surveying work and more surveyors will use photogrammetry tools for mapping.  In other words, inexpensive data collected from drones has and will continue to blur the lines between photogrammetry and mapping.

There is another issue at play here.  The process of physically flying a drone is not unique to map making.  The type of data collected is determined by the instrument payload -- not by the drone operator.  In other words, it really doesn’t make any difference if the application is precision agriculture or mapping a pipeline, the deliverables are the information extracted and processed by the crop consultant, the photogrammetrist, or the surveyor.

Drone technology is moving extremely fast.  It’s very possible many surveyors would rather hire a service provider to collect data than invest in a tool that can be obsolete is as little as six months.  They may also consider short-term leases to ensure their technology is relatively current or just rent a drone when needed.  Regardless of how small drones fit into the workflow, they will not only affect the industry, but they will also create new opportunities for independent contractors who, based on their experience, may be able to fly and collect data less expensively than surveyors.  The value add is the knowledge and data processing skills of the surveyor and photogrammetrist, not their drone-flying skills.”

 

What is “survey grade accuracy”?

There are numerous tasks and projects in which accurate measurement of 3D points is critical. A few examples might be mapping, construction, communications, and ownership boundaries and other civil law applications.

Survey Grade Accuracy

The degree of accuracy that would be expected in such projects depends on the final application and intended use of the survey or mapping data. The acceptable could be a foot or more away from its actual surveyed location, and in some projects, the maximum acceptable error is only two to three inches or less. According to the USGS Global Navigation Satellite System Committee it is the surveyor's responsibility to know the accuracy requirements of the survey and match this with the accuracy of his or her receiver in combination with the accuracy of the correction information being received based on correction quality and location. Most survey grade equipment has horizontal and vertical accuracy based on distance. Therefore when roving in RTK mode the vertical accuracy of the surveyed points in relation to the base station 8 km away is 2 cm + 1.6 cm or 3.6 cm. The further a survey is from the correction information, the less accurate the survey. 

Traditionally, a professional land surveyor must be both accurate and precise, and as you might expect, reaching survey grade accuracy by manual field-survey measurements can be extremely time consuming -- not to mention, on inaccessible and uneven terrain, dangerous!

At DroneView Technologies, we pride ourselves on refining our aerial mapping data to the point that it meets the standard of American Society of Photogrammetry & Remote Sensing (ASPRS) Positional Ac­curacy Standards for Digital Geospatial Data (2014). With properly placed reference points (another blog to come on this topic later!), we can generate point clouds with a Root Mean Square Error (RMSE) of 3 to 5 cm (xyz) when compared to field surveyed ground control and check points. With drones, we can rival the accuracy of traditional mapping methods while bringing an innovative level of speed and safety to the table.

For more information, contact DroneView Technologies. Aerial Data Acquisition and Processing: Full Service. Trusted Solutions.

 

Drones and the Photogrammetry Process: Understanding the Basics

Drones + Photogrammetry are transforming traditional survey methods. As drones are beginning to pop up more and more in the aerial sphere, many of you may be wondering, “What exactly can these things do other than take pictures and videos?” Well, the truth is that is exactly what drones bring to the table: high quality images from hundreds of feet in the air. The real value that can be obtained lies in the processing of these images.

Photogrammetry

One of the main processes the images undergo here at DroneView Technologies is photogrammetry. Foh-tuh-gram-i-tree, as most people around the office struggle to pronounce correctly, is the process of making surveys and maps through the use of photographs, especially aerial photographs. More specifically, all the pictures taken from the drone are laid out side by side and compared to determine how many points they have in common with one another. These common points are used as “tie points” to stitch the photos together. The amount of overlap, or common area registered in between pictures, assigned to the drone before it flies is therefore a critical factor toward the quality of the output generated. Whether done manually through a pair of stereo-glasses or with powerful industrial grade software programs like Pix4D, the stitching of these photos can produce high density point clouds, sets of millions of points in an XYZ coordinate system.

From densified point clouds, we have the capability to generate anything from a 2-D orthomosaic to a 3-D digital terrain model for our clients. These types of output have a plethora of applications, including circling piles on a model to calculate volumes or tying in known coordinates to create high accuracy georeferenced maps. With drones and photogrammetric processing, the possibilities are endless!

For more information, contact DroneView Technologies. Aerial Data Acquisition and Processing: Full Service. Trusted Solutions.