Pixels-to-Points™: Easy Point Cloud Generation from Drone Images

Point cloud generated from 192 drone images using the Pixels-to-Points tool
A point cloud generated by EngeSat’s Laurent Martin using the new Pixels-to-Points™ tool in version 19 of the LiDAR Module. The LiDAR Module tool analyzed 192 high resolution drone images to create this high-density point cloud.

When we have a new product release like the version 19 of the LiDAR Module that comes with the Pixels-to-Points™ tool, it’s always exciting to see that feature in action for the first time outside of the Blue Marble office. Our South and Central American reseller Laurent Martin from EngeSat was quick to try the new Pixels-to-Points tool for himself using drone data collected by his peer Fabricio Pondian.

The new Pixels-to-Points tool uses the principles of photogrammetry, generating high-density point clouds from overlapping images. It’s a functionality that makes the LiDAR Module a must-have addition to the already powerful Global Mapper, especially for UAV experts.

Below, screenshots captured by Laurent illustrate the simple step-by-step process of creating a point cloud using the Pixels-to-Points tool and some basic point cloud editing using other LiDAR Module tools.

1. Loading drone images into the LiDAR Module

The collection of images loaded into the LiDAR Module must contain information that can be overlapped. The Pixels-to-Points tool analyzes the relationship between recognizable objects in adjacent images to determine the three-dimensional coordinates of the corresponding surface. In this particular example of the Pixels-to-Points process, 192 images are used.
The flight path of the UAV and the locations of each photo can be viewed over a raster image of the project site.

2. Calculating the point cloud from loaded images

192 high-resolution images are selected in this particular example. The tool will give an estimated time of completion, which depends on the size of the images and number of images.
The Calculating Cloud/Mesh dialogue displays statistics of the images as they are analyzed and stitched together by the Pixels-to-Points tool.
An alert window pops up when the process is complete.

3. Viewing the generated point cloud

A new layer of the generated point cloud is now in the control center.
A close up of the final processing result with the orthoimage.
A close up of the final result with the new point cloud generated from the 192 images.
A 3D view of the resulting point cloud.
A view of the point cloud colorized by elevation
A cross-sectional view of the point cloud using the Path Profile tool

4. Classifying the point cloud

Points can be reclassified automatically or manually using LiDAR Module tools. Here, the point cloud is reclassified as mostly ground points.

5. Creating an elevation grid and contours from the point cloud

With the point cloud layer selected, a digital terrain model can be generated by clicking the Create Elevation Grid button.
A cross-sectional view of the digital terrain model using the Path Profile tool
Contours can be generated from the digital terrain model by simply clicking the Create Contours button.

A quick and easy process

In just a few steps, Laurent was able to create a high-density point cloud from 192 images, reclassify the points, and create a Digital Terrain Model. It’s a prime example of how easy version 19 of the LiDAR Module and the new Pixels-to-Points tool are to use. Check out EngeSat’s full article on the release of LiDAR Module.

The Foils and Follies of Drone Data Collection

Drone collects imageryChelsea E | Projections
A drone flies over the Blue Marble Geographics headquarters in Hallowell, Maine collecting imagery to be used in software testing.

Over the past few months, the Blue Marble team has taken on the challenge of collecting drone imagery of our property for testing exciting new features coming soon to Global Mapper. As we began to step into the fairly new commercial UAV field, we realized that there are few assumptions we can make. First of all, there is a learning curve that comes with simply flying a drone to take pictures or collect imagery. There are also a number of legal hurdles, safety concerns, and practical challenges to consider. We needed guidance as we began this initiative, from which we learned a few important lessons.

Drone Flight Concerns and Considerations

Though it appears to be a relatively simple technical challenge, flying a drone has legal and safety considerations that were readily apparent to us but may not be common knowledge. Our first concern was that the Blue Marble headquarters are only about a mile and half, as the crow (or should I say UAV) flies, from the Augusta State Airport. Small planes fly overhead frequently and quite low at times. We were not sure if our building was located near banned airspace. Our second concern was that our property abuts the Hall-Dale elementary school playground. A location that is full of children three or four times a day during business hours. What if we crashed in the school yard while children were at recess? What a PR nightmare.

These concerns about the airport and school property were enough to stall us from simply buying or building a drone, and prompted us to seek guidance. Fortunately for us, the University of Maine at Augusta offers an unmanned aerial vehicle training course taught by certified pilots. A quick call to one of the faculty members for more information resulted in the gentlemen visiting our offices to conduct some test flights and to share a bit of their knowledge with us. We learned a great deal even from our first test.

Programming drone flight pathChelsea E | Projections
Certified UAV pilot Dan Leclair uses his laptop to set up a flight path for a drone to fly over the Blue Marble Geographics headquarters in Hallowell, Maine.

Setting Up the Drone for Flight

Certified pilots Dan Leclair and Greg Gilda joined us at our office on a beautiful, clear and wind-free day in early October. They confirmed that we could fly over our property with some stipulations, despite our location near a commercial airport. As a precaution, the gentlemen brought with them a hand-held radio to monitor pilot communication in the area as we set up our flight path. They also reassured us that there was little chance of the drone flying off of our property during school recess, since the drone would be programmed and flown on autopilot. Dan and Greg shared a litany of information about how the drones now have homing devices, automatically avoid collisions with structures, and fly on a pre-programmed flight pattern. If, for some reason, it did fly over school property, we could manually fly it back. We also learned that the drone must stay within our view to remain in compliance with Federal Aviation Administration (FAA) regulation, which was no problem. We weren’t flying a large area anyway.

As we chose and programmed the drone flight path with a laptop, the pilots focused on a very common issue for us GIS folks — proper elevation above ground. Since we are located in the descent path of planes landing at the airport, we needed to keep the drone relatively low to avoid any potential, and of course unwanted, collisions with an aircraft. We decided that we would fly at 100 feet above ground on a path that was 1,793 feet long and would take about 3 minutes.

Drone cameraChelsea E | Projections
We also set up the drone camera for the light conditions, and programmed it to capture an image every two seconds during the flight.

The software the pilots used had some short comings in that the user had to manually select points for the back-and-forth flight path we wanted. As a software guy, this seemed tedious. I would rather draw a quick polygon or box around my area of interest and have that converted to a flight pattern. Perhaps that could be a new feature for Global Mapper Mobile in the future? In this case, our area of interest was our building, so it did not take long to manually designate the flight pattern by selecting waypoints for the drone to fly back and forth. We also set up the drone camera for the light conditions, and programmed it to capture an image every two seconds during the flight. One practical lesson we learned was that a good staging area for the laptop is preferable on a sunny day. We used the back of an SUV for the shade, so we could see the laptop screen and comfortably program the software.

After a bit of work we were ready to fly.

Rotors are attached to droneChelsea E | Projections
Certified UAV pilot Greg Gilda puts the rotors on the drone before it’s sent on a flight path over the Blue Marble headquarters.

Flying the Drone and Collecting Data

We set the drone on a circular landing pad made of nylon near the back of our property. Greg attached the rotor blades, very carefully I might add. The blades attach rather easily to the quad copter by snapping into place. Dan explained that this step was done before turning the drone on, saying something to the effect of “you don’t want to lose a finger”.

Once the UAV was ready to fly we all stepped back. Dan launched it into the air with the touch of a button or two, and the drone began its pre-programmed flight path. For those experienced pilots, you might notice that we did not discuss ground control. More on that in a later blog entry, I suppose, but these early tests were not including that. The flight went seamlessly and Dan only took over manual control as he brought the drone in for a landing — a personal preference of his.

Everything seemed to progress well but we quickly learned that the drone ended up capturing only video (see below) and not still photography. A few more attempts later, we sadly learned that we would not be able to collect still imagery that day. Apparently there was some incompatibility with the flight planning software and the drone. Not to fear, they agreed to return another day after a software update to collect the imagery. So perhaps the most important lesson of the day was that, despite the best laid plans of mice and men, things do not always go as planned with drone data collection. If you’re interested in learning some more about the foils and follies of drone data collection visit this handy resource:  http://knowbeforeyoufly.org/

We’ll have more to share with you on this process and, of course, what we are doing with the data soon.

 


Patrick Cunningham


Patrick Cunningham is the President of Blue Marble Geographics. He has two decades of experience in software development, marketing, sales, consulting, and project management.  Under his leadership, Blue Marble has become the world leader in coordinate conversion software (the Geographic Calculator) and low cost GIS software with the 2011 acquisition of Global Mapper. Cunningham is Chair of the Maine GIS Users Group, a state appointed member of the Maine Geolibrary Board, a member of the NEURISA board, a GISP and holds a masters in sociology from the University of New Hampshire.

DroneMapper: Using Global Mapper for UAV Data Processing

Once the GRID generation is completed you have a bare earth DTM which can be exported as a GeoTIFF or any other elevation format via Global Mapper.

DroneMapper is one of the success stories in the fledgling field of UAV data collection and processing. After several decades of experience working in the aerospace industry, CEO Pierre Stoermer was quick to recognize the potential for drones as a viable low-cost alternative to manned aircraft for this purpose. Serving customers in a wide variety of industries and business sectors, including agriculture and mining, Stoermer recognized the importance of efficient data management and processing, both for their internal processes and for the value added products that the company delivers to their customers. This lead Stoermer to Global Mapper for UAV data processing.

CHALLENGES

Like most small businesses, one of the main challenges faced by DroneMapper was finding tools that provide the right level of functionality but that fit within the company’s inevitable budgetary constraints. As with any business expenditure, investing in technology must bring some degree of assurance that there will be a return on this investment. Traditional GIS applications are notoriously complex and cumbersome, requiring an inordinate amount of time and a high degree of training and expertise to effectively operate, which significantly impacts the overall cost of any project.

Without a dedicated GIS technician at DroneMapper, the operation and maintenance of the GIS data processing workflow is the responsibility of the current staff. The selected software must therefore be easy to learn and easy to apply.

DroneMapper has an expanding client and customer base, whose needs and requirements necessitate an efficient data processing platform that can generate deliverables in a wide variety of formats and with varying specifications.

A 3D view of piles in Global Mapper that were measured to give the viewer perception of their relative sizes.

SOLUTIONS

Unlike most companies who, when faced with a technology decision, evaluate multiple software alternatives, DroneMapper found Global Mapper first and has stuck with it. The range of functionality in tandem with the unparalleled format support were enough to convince them that Global Mapper was an ideal solution for their needs.

A visualization of what has been filtered from an initial point cloud and digital elevation model.

This versatile, fully functional GIS application has been steadily gaining an eager and dedicated worldwide following among geospatial professionals. Recent development work has focused on the visualization and analysis of 3D data, especially LiDAR and other point cloud formats. According to Stoermer, “Global Mapper provides an outstanding set of tools for efficiently assisting us and our client base in an affordable manner”.

GLOBAL MAPPER FOR DATA PROCESSING

Global Mapper is at the core of most of DroneMapper’s data processing workflows. The company employs the software’s intuitive 2D and 3D visualization tools to provide initial quality control of ortho-rectified imagery and DEMs.

Further along the production line, Global Mapper is the go-to application for filtering point cloud data to create accurate, bare-earth Digital Terrain Models. These DTMs allow the company to generate customized contour lines that can be exported in shapefile or virtually any other vector format. Global Mapper’s powerful cut and fill analysis capability and volumetric calculation tools are used to precisely measure volumes, providing DroneMapper’s clients in a variety of industries with site-specific intelligence that is essential for efficient project management.

Employing Global Mapper’s powerful raster calculation functionality, DroneMapper is able to quickly and accurately analyze vegetation patterns by generating NDVI grids. This provides an invaluable service to clients in the agriculture and forestry industries.

BENEFITS

DroneMapper’s decision to settle on Global Mapper for its spatial data management allows the company to perform both internal data processing as well as customer services on one powerful and easy-to-use platform. The application’s SDK will also provide an opportunity for future custom development projects and will allow DroneMapper to adapt Global Mapper to more specifically meet their needs.

ABOUT GLOBAL MAPPER

Global Mapper is an affordable and easy-to-use GIS application that offers access to an unparalleled variety of spatial datasets and provides just the right level of functionality to satisfy both experienced GIS professionals and beginning users. Equally well suited as a standalone spatial data management tool and as an integral component of an enterprise-wide GIS, Global Mapper is a must-have for anyone who deals with maps or spatial data. The supplementary LiDAR Module provides a powerful set of tools for managing point cloud datasets, including automatic point classification and feature extraction.

ABOUT BLUE MARBLE GEOGRAPHICS

Trusted by thousands of GIS professionals around the world, Blue Marble Geographics is a leading developer of software products and services for geospatial data conversion and GIS.  Pioneering work in geomatics and spatial data conversion quickly established this Maine-based company as a key player in the GIS software field.  Today’s professionals turn to Blue Marble for Global Mapper, a low-cost, easy-to-use yet powerful GIS software tool. Blue Marble is known for coordinate conversion and file format expertise and is the developer of The Geographic Calculator, GeoCalc SDK, Global Mapper, LiDAR Module for Global Mapper, and the Global Mapper SDK.