LIDAR Magazine

Want to Practice Photogrammetry in Florida, You Gotta Be a Surveyor!

I love living in Florida, the weather, the beaches, the attitude, and the Hockey…Go Bolts! These are all great reasons to pack your bags, leave your coats and ice scrapers behind and head on down to join us in preretirement. However, there are also negatives to living in Florida. It can get quite hot in the summer, and humid if you live inland. The central part of the state (Orlando) is just theme parks, tourists, timeshares and traffic. My advice is to stick to the coasts.

Editor’s note: A 925Kb PDF of this article as it appeared in the magazine, complete with images, is available HERE

From a geospatial professional’s prospective, there is also a downside. In the State of Florida, to practice photogrammetry, you must also be a surveyor and have the designation of Professional Surveyor Mapper (PSM). Florida is one of a handful of States that does not recognize photogrammetry as separate from surveying, even though there is a nationally recognized photogrammetry certification process governed by the American Society of Photogrammetry and Remote Sensing (ASPRS). I am one of these; a Certified Photogrammetrist (CP).

I started my career as a surveyor in the US ARMY. I learned how to survey at the Defense Mapping School (DMS) and surveyed in many cool places around the world. Back then surveying was old school (Pre GPS), plane tables, theodolites, levels, and chains. I could turn angles and close level loops with the best of them, but I knew even then surveying wasn’t going to be my long term gig.

I absolutely respect and understand what surveyors do as I have walked in those shoes, but my head has always been in the clouds or rather in the air (not full of air, I heard that). I grew up in a family owned aerial photography business and the images we captured and what our clients used them for was far more interesting to me than survey. So I began doing some research on the subject. First I googled it on the internet… wait those didn’t exist yet. One of our clients, Tom Rattray, owner of Rattray and Associates taught Photogrammetry at the local college and he showed me what they were doing with our imagery. Tom ultimately offered me my first job in photogrammetry. The common link between surveying and photogrammetry is that they are both based on math my visual brain can understand…geometry. I’ll leave the higher forms of math out of it for now.

I won’t go into details in this article on the birth of photogrammetry and who contributed what to the process…you can Google it, but basically photogrammetry (using aerial imagery) facilitates the mapping of areas where access from the ground is limited or the area is just too large for conventional surveying. Using photogrammetry, a map can be made without ever touching the ground, More to the point, without a surveyor. Measurement can be made from these maps but only relative to the map itself. There are many variables that dictate the quality and reliability of your map; flying height, focal length, sensor quality, processing software and the skills of the technician performing the work all play a part. This is why we have a certification process. As with surveying, just because there is equipment and software that allows practically anyone to do it, doesn’t mean it’s being done right.

I stopped surveying prior to GPS. I’ve manned base stations and have a good understanding of how everything works. I need to know this as a photogrammetrist, because I rely on survey and surveyors to bring my maps from relative to absolute. I need surveyors to provide me with good quality photo identifiable control, placed where I determine it should go, at an accuracy level sufficient to support the mapping deliverable I produce. It may not sound like much, but it’s extremely important to my mapping.

One of the most tiring phrases I hear from surveyors when we talk about mapping is the protectionist mantra, “that sounds a lot like surveying to me.” No, it sounds exactly like photogrammetry. Not even a little like surveying.

If you’re a Florida surveyor (or from one of the other State’s that defines photogrammetry as surveying) I’m not picking fights here, but rather pointing out a problem we are each having in our profession(s). Companies are popping up all over because barriers to entry such as cost in equipment are falling and the promises of black box processing solutions make it easy for these folks to mistakenly claim they can produce accurate maps. As a CP, I spend a lot of my time trying to educate new entrants into the market, that a map produced from their drone and processed with Pix4D is at best a pretty picture without ground control to tie it down. Accuracy and Ground Sample Distance (GSD) are not the same, and a surface produced from black box software is not the same as one prepared by a photogrammetric technician working in a stereo environment.

We are now beginning to see UAS with RTK onboard, totally unnecessary but spend it if you have it right? Usually the claim that comes with these RTK systems is that you won’t need control. We’ve heard this before with Airborne GPS and IMU’s, but in reality we know better. Do you think these new entrants are going to get a surveying license? Not likely, or not many of them.

I’m a huge advocate of traditional photogrammetry, and I understand the need for good quality control to support projects where a high degree of accuracy is needed. Over the past 25 years I have contracted or managed surveyors who have set control for many mapping projects. It’s not in my wheelhouse to do the survey work anymore. I also understand that surveyors do way more than just set control for mapping projects, and their work carries a lot of liability. However, the definition of mapping is becoming blurry as part of this influx of new entrants and their clients who are looking for new deliverables. Models and visualization, merging of datasets, and monitoring of project sites over time. All of these things can “sound a lot like survey” but they aren’t or are , not intended to be.

The FAA has had to look at and adjust how we operate our airspace in a world where the future will include unmanned flight. As part of this, there has been a lot of education on: airspace, licensure, safety and regulations (along with the reasoning behind them). While there are serious bumps in the road and many complain the process is taking way to long, progress is taking place and we will see integration soon.

The surveying and mapping profession(s) in my opinion, also have to seriously look into how we integrate (or separate) new deliverables and technology into our professional environment. Education is going to play a huge part in this and it has to go way beyond our professional society’s and organization’s and meetings into the public where our new entrants are. I have advocated that the ASPRS become more involved in this on the photogrammetry side. I would hope the same is being done at NSPS. When new entrants understand the reasoning behind why something is considered survey and/or what type of deliverables can be produced from photogrammetry, its limitations, and the liability involved in errors they will be less likely to oversell these capabilities. Instead of just “that sounds a lot like survey to me” follow it up with why and maybe even how we could work together to provide a solution. I think surveyors and mappers would benefit from working together to define our future. Give and take…did you hear what those GIS folks are doing? They are pure evil!

Eric Andelin President Vertical Information Services, Inc. Mobile: 813.992.6612 E-mail:eric@vertx.biz Website: www.vertx.biz

A 925Kb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE

Exit mobile version