Blue Marble Monthly – LiDAR vs PhoDAR and Becoming a Pilot

Product News, User Stories, Events, and a Chance to Win a Copy of Global Mapper Every Month

For many, summer is a time for relaxing, for taking your foot off the gas, for being lazy. Not at Blue Marble. We are busy preparing for the next major release of Global Mapper in just over a month, planning our hectic autumn travel schedule, and making the final preparations for our 25th anniversary user conference here in Maine. In this edition of Blue Marble Monthly we formally invite you to join us at BMUC. We also hear from Sam Knight about becoming a licensed drone pilot; we discuss the differences between LiDAR and PhoDAR; and we challenge your geographic prowess in the Where in the World Geo-Challenge.

NEWS | BMUC is Coming to Portland, Maine

We hereby cordially invite you to Blue Marble’s home state for our User Conference (BMUC), as we continue to celebrate our 25th birthday. Not only will you have a chance to meet other users and learn about the latest software developments, but you’ll also hear from some interesting presenters including Ron Chapple who will be speaking about his work in the Pulitzer Prize-winning project, “The Wall”.

 

PROJECTIONS | Becoming an UAS Pilot

Ready for the kids to go back to school? Sorry, we can’t help you with that, but we recently sent our own Sam Knight back to school to learn what it takes to become a licensed drone operator. As we continue to develop tools for the UAV industry, it is essential that we have the first-hand knowledge of what is required. For Sam, this was a journey into unknown territory.

 

PRODUCT NEWS | Call for Beta Testers

Blue Marble’s development process has always relied on direct input from users and now you have a chance to be part of that process. Sign up as a beta tester today and we’ll let you know when a beta version of either Global Mapper or Geographic Calculator is available for you to put through its paces.

 

DID YOU KNOW? | LiDAR vs Photogrammetric Point Clouds

The Pixels-to-Points tool has caused quite a stir in the UAV industry. Creating a high-density 3D point cloud from a drone would have been unheard of just a few years ago. While the data may look and feel like traditional LiDAR, there are significant differences between the two formats. In a recent blog post, we outlined some pros and cons of each.

USER STORY | Planning Truck Stops with Global Mapper

In the latest Global Mapper case study, we hear from Michael Frings, General Manager of MFBI Technologies about how the LiDAR Module’s point cloud processing tools played a critical role in planning autobahn truck stops in Germany.

“The fact that the LiDAR Module is so powerful, giving us the ability to handle large point clouds, was the killer argument for us to go with Global Mapper.” – Michael Frings

 

 

VIDEOS | Can Your GIS Do This Without Extensions?

Simply stated, Global Mapper gives you more functionality for less money. Need proof? Take a look at this short video highlighting some of the terrain processing tools that are available out of the box in Global Mapper. No extensions required.

This and previous Blue Marble Webinars and Webcasts can be viewed at the Blue Marble YouTube Channel and on the Webinars page on the Blue Marble web site.

 

Where in the World Geo-Challenge

The geographic sleuths were once again hard at work in July. Most of you were able to identify all five locations in the Where in the World Geo-Challenge. The randomly selected winner of a copy of Global Mapper is Roy Mayo, a land surveyor from Mackay, Mackay, and Peters. If you are one of the handful whose response to the capital city question was, “Haven’t a clue” or words to that effect, check out the correct answers here then click the link below to see if you can do any better in August’s challenge.

 

See complete terms and conditions here.

EVENTS | Global Mapper Training in Houston

The Blue Marble training team will be hitting the road again in October with the next three-day Global Mapper class scheduled for Houston. Typically our Houston classes fill up fast so be sure to sign up as soon as possible to reserve your spot.

“Without a doubt, one of the most informative and enjoyable technical training classes I have ever taken.”
– Recent Global Mapper trainee

 

LiDAR vs Photogrammetrically Generated Point Cloud Data

A 3D mesh created using Global Mapper’s Pixels-to-Points tool displayed in the 2D and 3D views

While both LiDAR and PhoDAR are 3D point cloud formats, the process of creating each is completely different. The nature of the collection process dictates the structural characteristics of the data and its usefulness for specific applications.

In this blog entry, we look at some of the distinct differences between each collection method, and their ideal uses.

A screenshot showing conventional LiDAR data in Global Mapper colorized to represent elevation

LiDAR – The Good

Active Collection Process

Individual 3D points are collected and processed in real time.

More Return Data

Each point includes a range of useful data including return intensity, return count, and classification (added as a post process).

Data Sharing

Data structure has been standardized providing optimal conditions for data sharing and interoperability.

Wide-Area Collection

Scanners mounted on aircraft allow for a wide-geographic area to be captured relatively quickly.

Compact Equipment

Unlike early LiDAR hardware, scanners are now relatively compact and can even be mounted on a UAV.

Ground Detection

LiDAR can penetrate foliage and similar obstructions providing a complete 3D representation of the target area. This allows for ground detection even in heavily forested areas.

Rapidly Evolving Tech

For instance, Geiger-mode LiDAR can provide point densities of 100/sq m or greater.

Accuracy

The points are theoretically more accurate, especially the height value.

DTM Generation

LiDAR is ideal for generating Digital Terrain Models because, unlike photogrammetry, it can “see” through canopies to ground.

LiDAR – The Not So Good

High Cost

Traditional LiDAR requires a manned aircraft to house the necessary hardware.

Sensitivity to Flight Conditions

Collection requires optimal atmospheric conditions for flying. The altitude and speed of the aircraft can also effect the point density.

Poor Anomaly Identification

Raw LiDAR cannot recognize anomalies in the data (e.g. birds underneath the flight path)

Inconsistency in Processing

It is not uncommon to encounter publically available LiDAR files that have been erroneously classified

 

A split image showing a photogrammetrically generated point cloud on the left and a 3D mesh created form this point cloud on the right

PhoDAR – The Good

Minimal Technical Requirements

It’s a more accessible way of creating a point cloud with hardware that can cost as little as $1,000.

On Demand & Versatile Collection

Data can be collected on demand, in a relatively confined area, and with minimal preplanning required.

Greater Point Cloud Density

Point densities are typically much greater than those of traditional LiDAR

Classifiable Data

While not natively LiDAR, a photogrammetric point cloud can have classification values applied and can be exported to a las or laz file.

Raster-Colorized Points

Each point automatically inherits the color from the corresponding images.

DSM Generation

Ideal for Digital Surface Model generation since it is unable to penetrate vegetation like LiDAR can.

PhoDAR – The Not So Good

Requires Distinct Features

Points derived from image analysis require distinct visible features in the geographic area of focus.

Requires Surface Variety

Photogrammetric point cloud generation doesn’t work well when there is a lack of variety in surface texture in images, such as the surface of a desert area or large parking lot.

Requires Sufficient Light

Unlike LiDAR, photogrammetry depends on sufficient ambient light. Clear images are required for generating a point cloud, so shooting images in low-light conditions is not ideal.

Poor Ground Detection

Photographs cannot “see” through canopies like LiDAR can.

Shadows and Sky Don’t Work

Point cloud generation doesn’t work well with images that contain large shadows or a lot of sky.

Accuracy Depends on Ground Control

Horizontal accuracy and elevation values are not as accurate unless ground control points have been used in the processing phase.

Coverage is Usually Limited

Photogrammetric point cloud generation isn’t as practical for large area coverage.

Inconsistent Colors

There is often inconsistent coloring across a surface area due to variations in the color balance of the individual images

More Cleanup

Reflective surfaces can sometimes cause more noise points or anomalies in the data, which would require manual removal. Finer features, such as power lines, may not show up as well as they would in LiDAR data.

Ideal Uses for LiDAR

LiDAR is ideal for collecting data of larger areas and of finer details, such as power lines, pipe lines, and the edges of objects. It’s also ideal for creating digital terrain models, since sensors can penetrate vegetation, allowing for the collection of real ground points.

Ideal Uses of Photogrammetry

Photogrammetry is ideal for surveying smaller areas that contain minimal vegetation. Since it can’t penetrate vegetation like LiDAR, photogrammetry is often better for generating digital surface models, rather than terrain models.

Ideal Software for Both LiDAR and Photogrammetry

Whichever point cloud generation method you choose, Global Mapper and the LiDAR Module are well-equipped to efficiently and effectively process the resulting data. The extensive list of editing, visualization, and analysis tools include point cloud editing and filtering, DTM or DSM creation, feature extraction, contour generation, volume calculation, and much more.

Where in the World Geo-Challenge – August 2018

View the form at Google Forms >

Where in the World July 2018 Answers

How Well Did You Do?

Name the country – Monaco

 

 

 

 

 

 

 

 

 

 

 

Name the mountain – Denali (Mt McKinley)

 

 

 

 

 

 

 

 

 

 

 

Name the body of water – White Sea

 

 

 

 

 

 

 

 

 

 

 

Name the UNESCO World Heritage Site – Acropolis of Athens

 

 

 

 

 

 

 

 

 

 

 

Name the capital city – Canberra

 

The Path to Becoming a UAS Pilot

Chelsea E | Projections
Dan Leclair, one of the flight instructors of the Unmanned Aerial Systems (UAS) program at the University of Maine at Augusta, prepares to fly a drone over the Blue Marble Geographics headquarters in October of 2017.

A fool thinks himself to be wise, but a wise man knows himself to be a fool.
-William Shakespeare, As You Like It, Act 5, Scene 1


With any new endeavor, you often start out with little idea of the depth of your lack of knowledge until you get going. Last year, as we started working with drone imagery for the Pixels-to-Points tool here at Blue Marble, we realized we were going to need to actually do our own flying to really generate the kinds of quality testing data we wanted to be working with for developing structure-from-motion tools and other new processes that take advantage of drone generated data. To fly commercially, we knew we needed a Part 107 certified remote pilot on staff and after some discussion we decided that I would become that pilot. We all knew there was a knowledge test involved and that it would be a good idea to take a prep course, but we were at the point where we didn’t know what we didn’t know.

Luckily, we are about a mile from the University of Maine at Augusta, which happens to be developing an Unmanned Aerial Systems (UAS) program within the Aviation department. We had met Dan Leclair, one of the flight instructors, at a local conference and realized we had some knowledge to exchange. He and Greg Jolda, another of the instructors, came over to the Blue Marble headquarters with one of their drones to do a flight around our grounds collecting images that we could run through early versions of the Pixels-to-Points tools. Now, where we are located specifically, just happens to be on the approach to the Augusta State Airport. Dan and Greg gave us a crash course in wind speeds, flight waivers, radio communication, and airspace ceilings … or roughly enough to make a GIS practitioner’s head spin in under five minutes. The drone wasn’t even out of the case yet!  There’s an old saying that an expert is someone who knows a lot about a little. We know maps, geodetics, and data analysis here and we were realizing that this was going to have a large learning curve ahead; I was going to need to become an expert in a whole other field.

Chelsea E | Projections
Greg Jolda, an instructor of the Unmanned Aerial Systems (UAS) program at the University of Maine at Augusta, adjusts a rotor on a drone at the Blue Marble Geographics headquarters in October of 2017.

Class: Learning to become a pilot at night

Fast forward to my first night of class. The course would be two nights a week for eight weeks, in three-hour class meetings, led by Dan and Greg.  It had been rather a long time since I had been on the other side of the lectern in a classroom. Let’s just say laptops were not common the last time I took a class. I was rather excited; I love learning new things and applying that knowledge. The room started to fill up and we started getting to know each other with some introductions. We were from many different fields: foresters, engineers, radio tower operators, real estate agents, photographers, media company producers, scientists, and even some self-starters looking for a new line of work. Basically, everyone there was looking into a new area. Going over the course syllabus and reading materials, it was readily apparent what we didn’t know: A LOT.  General regulations, pilot certification, airspace classification and restrictions, aeronautical chart interpretation (Yay, maps!), airport operations, weather, weight and balance, aircraft performance, radio communications, aeronautical decision-making, emergency procedures, maintenance, pilot physiology, on and on.

Every topic comes with vocabulary specific to flight operations, even getting into nitty gritty stuff such as how to pronounce numbers over a radio and how to read a weather report written in shorthand code. Throughout the weeks, we covered all of these topics and more. Every time we entered a topic it was a good education in just how little you can imagine is involved outside the things you already know. We found that everyone in the class had their own challenges. Being a generally spatial thinker, the mapping sections and airspace designations I found simpler than some of the more abstract bits of weather such as the different types of clouds and how to read them. Others struggled with airspace but had no trouble with the physics-heavy sections of loading, altitude density of air, etc. There’s a wide variety of topics involved and it takes time to assimilate the sheer breadth of new information that’s covered on the exams.

Chart of airspace
A chart illustrating airspace published in the Federal Aviation Administration’s Pilot’s Handbook of Aeronautical Knowledge.

One of the questions a lot of my friends and colleagues have asked me is: “How do you practice flying at a night class?” It makes sense, it’s a drone pilot class, you’re going to learn to fly, right? Well, no. You don’t actually have to have flown a single minute to become a Part 107 certified pilot. The test is purely knowledge-based, and is intended to ensure that drone pilots know how to operate safely within the federal airspace. In our class we did actually spend some time flying small Blade Inductrix drones indoors with full size Spektrum DX8 transmitters towards the end of the course. We also spent some time talking about the basic mechanics of fixed-wing and multi-rotor builds, and their control systems. This is not really essential to prepare for the Part 107 exam, but it is good material to cover.

So, at the time of writing, I’ve arrived at the end of the course. Tomorrow morning I go on for my exam. I have been taking practice exams on the Gleim test prep system until I’ve started to recognize some of the 900 practice questions. I have never failed a practice exam, so I’m feeling good.

Testing: Knowing your airspace, safety, and weather

I passed.

From the questions on the exam, it’s very clear where drone pilots have been having issues:  airspace & operations! The breakdown of questions I encountered was about 50 questions on airspace and general safety practices and the last 10 questions on weather. I did pretty well on the test, passing comfortably. Going back through the review of things I missed (which it lets you do upon completion), I knew which questions I was shaky on. There was one question on an airport-related topic that I know I had never seen the answer to before. The test procedure itself is pretty simple, if you’ve taken practice tests on Gleim, you’ll be right at home on the FAA test system, it looks and feels pretty much exactly the same. The difference is that in Gleim, you work off of digital graphics for the charts and diagrams, and in the actual test you’re working out of a paperback copy of the Airman Knowledge Testing Supplement for Sport Pilot, Recreational Pilot, and Private Pilot (FAA-CT-8080-2G), which honestly, is easier to read than the digital practice graphics.

If you aren’t familiar with either, you have a simple panel-based interface on screen. Down the left you have your list of questions 1-60, and the main part of the screen has your questions and possible answers which are multiple choice and three options. You can mark questions to come back to later, which is very handy for taking a pass through and answering the ones that you are 100% confident in and then going back to spend more time on the others. I found two questions that I knew I would need to spend more time, because of the tricky wording. Even after spending some time looking through the book for some hints on those two, I was done in under 40 minutes. Having an hour and 20 minutes left, I used the opportunity to read through the entire test again and double check all my answers. I didn’t find any that I disagreed with myself on, so confidently I ended the exam to submit, the results go straight to the FAA, and I was immediately notified that I passed. All in all, a relatively procedural exam process after much preparation.

Getting the certification card in the mail was a relief after all that time studying, preparing, and then ultimately waiting.

Certification: Waiting for the card after weeks of preparing

You walk out of the testing facility with a stamped certificate that you passed the test, then the waiting starts. This certificate only states that you passed the test, it’s not actually your Part 107 certificate. You can follow your certification progress through the FAA’s IACRA website. In about 48 hours, it updated to show that it knew I passed the test, then over the next few weeks it updated as my results were passed around in the FAA systems, until eventually, I was granted a printable temporary certificate I could fly with. With this temporary certificate, there is no certificate number you can use to fill out waiver applications, but at that point I could legally fly. My certificate card arrived about six weeks after I took the test, backdated to the test date. Getting the card in the mail was a relief after all that time studying, preparing, and then ultimately waiting. I learned more than I could have imagined at the start and like I mentioned at the beginning of this entry, I now have a better idea just how much more there is to learn.

 


Sam Knight

 

Sam Knight is the Director of Product Management for Blue Marble Geographics. With Blue Marble for more than 14 years, Sam has lead hundreds of GIS and Geodetics courses and is a frequent speaker at industry conferences, trying to make tricky geodetics concepts accessible at a practical level.