UAV/UAS (Drones) And Land Surveying


By Michael D. Knopf, PE, PLS – Principal Engineer/Land Surveyor


Do I really need a Land Surveyor’s License for that?

This article examines the use of Drones in Land Surveying and mapping, differentiating the roles and responsibilities of the Land Surveyor from that of the UAS operator.  While these roles may appear to overlap, each has its own set of laws, rules and regulations.


The profession of land surveying has been experiencing a technological sea-change, its tools and technologies transitioning from the Iron Age to the Space Age in a single generation. Within that short time period, surveyors have transitioned from using antique instruments, hand calculations and bound field books, to powerful new technologies such as electronic total stations, computing, electronic distance measurement (EDM), global positioning systems (GPS/GNSS) and robotics.

Today the surveying profession is completely dependent on the digital environment. The development of many advanced electronics, automation and computing tools has presented new challenges for surveying professionals. Like other professions, surveyors sometimes have a difficult time learning and adapting to this unending flow of disruptive new technologies. Often the earliest adopters of a new technology are not surveyors, but those whose primary skill is the new technology itself rather than the technical principals that ought to govern its proper use. For example, when GPS signals were ordered unscrambled by President Bill Clinton on May 1st of 2000, geodetic coordinates could theoretically be determined by anyone, simply by pressing buttons on a GPS device operating as a “black box”. Unfortunately, non-surveying professionals were mostly unaware of the limitations of such things. People, even educated geospatial professionals, often lack a complete understanding of different horizontal and vertical datums. Sometimes, hardware and software vendors suffer similar weaknesses and as a result, they are prone to advertise capabilities that are not always accurate.


The latest new technology to emerge in the mapping world is UAV/UAS, which is a confluence of all the earlier mentioned technologies.  UAS combines GPS, robotics, automation and computing in a single system.  Having some of the same “black box” characteristics as GPS, these amazing “flying robots” can present similar risks from use by non-surveyors who try to provide mapping solutions depending entirely on the magic of the software and results provided by the “black box”. Without having a solid understanding of the limitations of the system or the surveying principles involved, operators can unknowingly provide outputs that contain serious errors.

Regulatory changes by the Federal Aviation Administration (FAA) in June of 2016 have unleashed a flood of new UAV/UAS users. By the way, UAV stands for unmanned aerial vehicles, referring to the aircraft itself, while UAS stands for unmanned aerial systems, which more broadly encompasses the aircraft, navigation systems, sensors, controllers, and any associated software and data processing apparatus. When used for any commercial purpose, FAA Part 107 regulations now treat all types of unmanned aircraft between 0.55 lbs. and 55 lbs., (including payload) as serious aircraft, requiring registration, strict operating rules and a commercial UAV pilot’s license to operate.  While pilot certification is required, the UAV regulatory environment is still developing, and it has been characterized by some as “the wild west”. The government has decided to take a light grip for the time being and let the technology “cook” for a while before adding new regulations and standards. Important safety factors such as aircraft maintenance, airworthiness, recordkeeping etc. are still, for now, the responsibility of the operator.

QK’s UAV – Matrice 600 Pro with RTK/GNSS Positioning

With the increase in drone operators, the marketplace has quickly recognized the value of UAV’s. The ability to safely gain visual access from an aerial vantage point has increased the demand for all types of services. Construction and industrial applications have already recognized significant benefits, particularly for locations or activities that fall into the dirty, dull, or dangerous categories, where drones offer significant advantages. The addition of sophisticated navigation systems, advanced sensors (especially better cameras) and automated software has added tremendous value to this technology, but it has also created the potential hazards mentioned previously, which certain users need to be aware of.

A specialized group of drone operators has begun developing applications for UAS in aerial mapping. Members of organizations such as Management Association for Private Photogrammetric Surveyors (MAPPS) and the American Society for Photogrammetry and Remote Sensing (ASPRS) have begun testing UAS mapping applications using low altitude, high resolution photogrammetry and LiDAR, achieving results comparable with traditional manned photogrammetry missions.  A more limited number of land surveyors have gone even further. Undertaking extensive testing, some have achieved map accuracies with UAS comparable with terrestrial GPS surveys. These results are very exciting, both on a cost basis and in terms of the richness of the data being produced, likely indicating the next great advance in surveying and mapping technology.

However, UAS operators and their clients can get into serious trouble by relying only on the “black box” aspect of the system without the guidance of an experienced land surveyor or mapping professional. As already mentioned, despite the claims of various equipment and software providers, black box hardware and software solutions cannot by themselves, always be relied upon to produce desired results. When considering use of UAS for mapping purposes, it is important to adhere to Rule 415 adopted by the Board of Registration for Professional Engineers, Land Surveyors and Geologists, which states:

“A professional engineer or land surveyor licensed under the code shall practice and perform engineering or land surveying work only in the field or fields in which he/she is by education and/or experience fully competent and proficient.”

This mandate is especially applicable to UAS technology when used in mapping applications. Traditional standards of accuracy such as National Map Accuracy Standards were developed in an age of paper maps and are not easily applied to newer mapping systems. To better relate to the types of digital map data being produced today, ASPRS has developed a digital accuracy standard more suitable for UAS mapping applications called “ASPRS Positional Accuracy Standards for Digital Geospatial Data”. This change is important because land surveyors and photogrammetrists no longer provide only two-dimensional maps as their end-product deliverable. With digital data captured in three dimensions, the options for deliverables might just as easily be a series of measurements, a three-D model, a CAD surface or a domain-ready dataset.

3D Model Generated from UAV Data


Same Image Showing Detail Possible with High Resolution Imagery

Outputs Using uas

It should also be pointed out that producing certain outputs using UAS without the involvement of a certified photogrammetrist or licensed land surveyor is not only unreliable, it is also against the law.  State land surveying statutes are clear in defining the required role of the licensed land surveyor or photogrammetrist. Section 8726 of the Land Surveyor’s Act defines land survey practice to include any of the activities listed below, almost all of which can occur with any mapping project utilizing UAS:

(a) Locates, relocates, establishes, reestablishes, or retraces the alignment or elevation for any of the fixed works embraced within the practice of civil engineering, as described in Section 6731.

(b) Determines the configuration or contour of the earth’s surface, or the position of fixed objects above, on, or below the surface of the earth by applying the principals of mathematics or photogrammetry.

(g) Determines the information shown or to be shown on any map or document prepared or furnished in connection with any one or more of the functions described in subdivisions (a), (b), (c), (d), (e), and (f).

(i) Procures or offers to procure land surveying work for himself, herself, or others.

(m) Creates, prepares, or modifies electronic or computerized data in the performance of the activities described in subdivisions (a), (b), (c), (d), (e), (f), (k), and (l).

(n) Renders a statement regarding the accuracy of maps or measured survey data.

While the UAS operator or drone pilot is required to be knowledgeable about flight operations, airspace, flight characteristics of the aircraft, weather, FAA regulations and pre/post-flight procedures, etc. these factors, important as they are, do not address the other critical aspects of planning a mapping mission. Other critical elements for a successful mapping mission include an understanding of the clients required map accuracy, density and location of ground control points, proper sensor selection, proper flight altitude and ground speed, location and number of required ground check points, flight pattern overlap, to name a few. For these activities, as well as post-processing of data, quality control, etc. a licensed land surveyor or photogrammetrist must be in responsible charge.

It should be noted that many commercial UAS applications do not involve mapping and therefore do not require a land surveyor or photogrammetrist. The images that can be produced from even a modest camera sensor mounted on a low-altitude UAV can be stunning and capturing these high-resolution images for a variety of purposes is one of the most valuable uses of UAS. Most of the time this type of work does not fall within the definition of land surveying or photogrammetry, that is, unless it is accompanied by certain representations.

Qualified Mapping Professional

How can you know when the use of UAS might also require a qualified mapping professional to be involved? In discussing the planned work assignment, listen for project objectives that use certain words such as acreage, area, dimension, location, contours, volume, accuracy, scale, coordinates, or units of measurement such as acres, feet or cubic yards. These words usually indicate work intended to provide a geo-positional, relational or dimensional reference and as such are likely describing activities that should be performed under the direction of a properly qualified licensed land surveyor or photogrammetrist.

While the Land Surveyor’s Act regulations do restrict certain types of UAV activities, they hardly make a dent in the rapidly expanding number of other potential uses for this amazing new technology. When considering use of UAS, it is important to understand these distinctions.

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3-Dimensional Terrain Model with Contours

Additional resources on the subject can be found at the links below:

About the Author

The author, Michael Knopf is a licensed Land Surveyor and Civil Engineer in California, Nevada and Arizona. He is also a licensed private pilot and Part 107 Commercial UAV pilot. First licensed as a land surveyor in 1977, he stepped down in 2018 after 12 years as President and CEO of QK and returned to a technical and supervisory role including leadership of the company’s Land Surveying practice.  QK is a multi-disciplined surveying, engineering, planning and environmental firm with California offices in Bakersfield, Porterville, Visalia, Clovis, Merced and Roseville.  The firm boasts nine (9) Part 107 Commercial UAV pilots and flies seven (7) UAV’s throughout the company’s practice areas, including surveying.

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