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.

What is BMUC? | An Embodiment of Blue Marble Values

Sam Knight speaks at BMUCChelsea E | Projections
Blue Marble Geographics’ Product Manager Sam Knight presents the latest features in Geographic Calculator 2017 to Blue Marble User Conference attendees in South Portland, Maine.

In my first couple of weeks as graphic designer at Blue Marble Geographics in 2016, I heard my coworkers use an unfamiliar term in our marketing meetings. They said things like: “do we have bee-muck speakers yet?”; or “when is the bee-muck e-mail going out?”; or “the bee-muck numbers are looking good so far.”

What the heck is a “bee-muck”?!

BMUC Amsterdam
Blue Marble Geographics took the BMUC experience to Amsterdam in spring of 2017.

I figured it was one of dozens of conferences that Blue Marble attends each year, like AUVSI or InterGeo, and not a term used to describe mud on a yellow and black insect pollinator. “Bee-muck” is actually how the Blue Marble team pronounces the acronym BMUC for Blue Marble User Conference, and BMUC is not just another event the company attends. It’s a series of conferences organized by Blue Marble in cities around North America (and sometimes the world) to show appreciation for the users of Blue Marble software. The one-day conferences offer users a chance to chat face-to-face with Blue Marble team members, to hear success stories from GIS peers, and to share a meal with everyone. I admit, I was skeptical when I heard the “share a meal” part. But when Blue Marble hosted a BMUC in Maine, I had the opportunity to take part in the rich experience the conferences actually have to offer.

Product News that Fosters a Collaborative Culture

At every BMUC, Blue Marble software specialists give talks on the latest product news. During the presentations at the Maine conference, I noticed one phrase that prefaced most of the announcements about new software developments — “We received requests for this feature.”

Patrick Cunningham speaks at BMUCChelsea E | Projections
Blue Marble Geographics President Patrick Cunningham welcomes attendees to the Blue Marble User Conference in Maine.

Global Mapper and Geographic Calculator have evolved into the cutting edge software they are today because of user feedback. Whether a user emails, calls, sends a Facebook message, or speaks to a staff member at a BMUC or other conference, the team at Blue Marble hears and considers what that user has to say. A couple of examples of user-requested features that were highlighted at the Maine BMUC were Global Mapper’s advanced attribute editor, which allows for streamlined editing of data assigned to map features; and the real-time hillshading feature, which allows for dynamic positioning of a light source by clicking and dragging a sun icon.

When asked about what new features of Global Mapper v19 came from user requests, Product Manager Sam Knight began listing them off:

  • The new attribute editor function
  • Playing multiple videos attached to a feature
  • The dynamic hillshading control
  • All the new raster band math formulae, which include Normalized Difference Snow Index (NDSI) and Advanced Vegetation Index (AVI)
  • Drag and drop docking for the 3D viewer and path profile
  • Exporting/importing flythrough paths

After giving this handful of examples, he stopped himself and said, “Actually, literally every significant new feature is a user request.”

The point I’m trying to make is that the product news shared at BMUCs not only keeps users in the loop, but it also fosters the collaborative culture that makes Blue Marble software great. It lets users know that they have a hand in improving these already powerful tools.

Alex Gray speaks at BMUCChelsea E | Projections
GIS Specialist Alex Gray of GEI Consultants Inc. presents on a hydrology analysis for which he used Global Mapper to create digital terrain models.

Peer-to-Peer Learning in the GIS Community

There are at least two guest speakers at every BMUC, who share their real-life experiences using Blue Marble products. These professionals come from a variety of GIS backgrounds — from oil and gas to filmmaking; from city planning to conservation. While members of the Blue Marble team bring their software expertise to the BMUC agenda, the stories from others in the GIS community add valuable outside perspectives.

Thea Youngs speaks at BMUCChelsea E | Projections
GIS Specialist Thea Youngs presents on how she uses Global Mapper for LiDAR processing in city projects for Portland, Maine.

At the Maine BMUC, attendees heard from GIS Specialist Thea Youngs, who uses Global Mapper for Portland city projects. She explained how the software fits in her workflow, and how fast it is to view and select an area of interest from a large point cloud. “Global Mapper helps with making LiDAR data play better with drafting software.” She also commended Global Mapper for its extensive list of supported file formats, since her work sometimes deals with older and less common formats.

Attendees also heard from GIS Specialist Alex Gray of GEI Consultants Inc., whose presentation focused on a hydrology analysis for which he created digital terrain models from a combination of LiDAR and sonar data in Global Mapper.

While both speakers use Global Mapper and the LiDAR Module for their powerful point cloud processing functionality, both work with very different workflows and could provide unique ideas on how to use the software. The presentations, as well as the variety of occupations in the BMUC audience, exemplified how versatile Global Mapper is and how BMUCs are a great place to share tips on how to use the software.

Let’s Call it Lunch, not “Networking”

It’s probably safe to say that the word “lunch” elicits a positive reaction from more people than the word “networking”. I mean, who can’t bond over a good sandwich?

BMUC lunchChelsea E | Projections
Attendees line up for lunch at the Maine Blue Marble User Conference.

During lunch at the Maine BMUC, attendees had the opportunity to share their own stories, ask more questions, discuss projects with their peers, and to make connections in their local GIS community. I was able to hear from attendees about what developments they’d like to see from Blue Marble in the near future, like the ability to create point clouds from drone imagery, which is actually something that Blue Marble is currently testing.

Other than providing lunch, Blue Marble also offers opportunities to win prizes such as T-shirts and a license of the latest version of Global Mapper. At the Maine BMUC, this opportunity came in the form of a “Name That Country” game, in which attendees had to identify countries from a series of slides.

An Affordable and Rich GIS Experience

After the conference, two thoughts struck me as I drank a beer with my co-workers and BMUC attendees who were able to join us for happy hour. My first thought: How cool is it that this small company can serve customers all over the world and still have intimate events like BMUCs? Second: BMUCs truly embody the user-focused mission of Blue Marble.

They are an affordable opportunity (only $25 to register) to gain insights from company experts and other GIS professionals; to meet new people in the GIS community; to win a copy of the latest version of Global Mapper; to have an opinion about a Blue Marble software and to have it heard; and did I mention lunch?

As I write this entry, the Blue Marble team is planning its BMUC 2018 schedule. Drop us a line at bmuc@bluemarblegeo.com if you’d like to see this experience come to your neck of the woods, and keep an eye on the BMUC page to find out where we will be next.

There’s an abundance of knowledge to be shared in the GIS and Blue Marble community, and BMUC is a tap on the barrel. Cheers!


Chelsea Ellis


Chelsea Ellis is a graphic designer and social media manager at Blue Marble Geographics. Her responsibilities range from creating the new button graphics for the redesigned interface of Global Mapper 18 to editing promotional videos; from designing print marketing material to scheduling social media posts. Prior to joining the Blue Marble team, Ellis worked in page layout and graphic design at Maine newspapers, and as a freelance designer and photographer.

Got LiDAR? Now What?

LiDAR Extraction in Global Mapper
Using Global Mapper‘s Path Profile tool to precisely digitize the edge of a curb from terrestrial LiDAR data.

The availability of LiDAR data is expanding at a rate that is out-pacing the requisite knowledge and skills needed to effectively utilize the data. Sounds like a cart-before-the-horse analogy, to coin an idiom from a bygone era.

This conundrum first came to our attention a couple of years ago when, during a roundtable discussion at a GIS forum in one of our neighboring New England states, a local government official excitedly announced that her town had just received LiDAR (or leader, to use her exact pronunciation) from the state. She went on to confide that she wasn’t entirely sure what LiDAR was but evidently that did not dampen her excitement. Remarkably, several other forum delegates jumped on the bandwagon, to use another obsolete transportation-based analogy, and shared their enthusiasm at having received data for their town while eagerly awaiting instructions from the same state agency on what to do next.

In the months that followed, it became clear that LiDAR illiteracy is not unique to small-town New England. Many GIS agencies and departments in other states, provinces, and regions throughout the world, recognizing the increased accessibility of point cloud collection technology, have proactively embarked on massive data collection projects. As a means to justify the expense of these projects, the agencies will often provide the fruits of their endeavor to eager and yet uninformed constituents and office bearers.

The aforementioned municipal officials were certainly justified in their excitement; LiDAR data is contributing to a fundamental change in how we perceive our world. Traditional mapping practices have considered the planet from an inherently unrealistic, top-down perspective. With the emergence of 3D data formats, we are now able to develop a more realistic view allowing us to interact with our data in an immersive environment and providing the impetus for the development of new cartographic and analysis techniques.

What is LiDAR?

Let’s make one thing clear, in most circumstances, LiDAR data is not a product but a raw material. It is not an end in and of itself but rather a means to an end. A commodity, if you will. Before exploring some examples of the products that can be created from LiDAR, let’s put the brakes on (yes I know, another transportation metaphor) and consider the basic structure and characteristics of LiDAR data.

The basics of collecting LiDAR data from an airborne platform.Illustration by Chelsea Ellis

Natively, LiDAR (an acronym of Light Detection And Ranging) is a vector data format, or more specifically, it is a 3D point vector format. Each LiDAR file or dataset usually contains millions, or sometimes even billions of closely spaced, randomly distributed points, with the closeness of the spacing dependent on how the data was acquired. Most publicly available LiDAR data has been collected on an airborne platform using laser transmission and receiving technology in tandem with precise position and navigation systems. Each point is attributed with an X, Y, and Z value derived from the calculated time difference between the transmission and reception of a reflected laser pulse. An aircraft flying lower and slower will create a point cloud with more closely spaced points than one flying faster at a higher altitude. Depending on how the data was collected and/or processed, additional attributes might include, a color value, reflection intensity, and the number of returns per pulse, all of which can be visualized and analyzed.

What Can You Do With LiDAR Data?

Fully utilizing LiDAR usually involves some sort of transformation process. This transformation might involve the creation of a 3D raster surface, often referred to as a Digital Elevation Model (DEM), or it might entail the automatic creation or extraction of 3D vector objects derived from the geometric patterns in an array of points. Both of these procedures will be described in more detail later. It is also possible to derive meaningful information by simply changing how the point cloud is represented. The point display can show the distribution of the different surface-type classifications; the elevation of each point above ground; variations in the density of the points; and many other characteristics.

Editing and Filtering LiDAR Data

Almost without exception, LiDAR data files will include many more points than are needed for a particular project or task. In Global Mapper, there are numerous filtering options for removing points that are outside of the geographic extent of a project area; that are considered erroneous or noise points; or that are attributed with a surface-type classification that is not required. Before embarking on any point cloud filtering procedure, it is a good idea to scrutinize the metadata for the layer. This statistical summary will provide the necessary information about the characteristics of the point cloud to allow more informed decision-making in the filtering process.

Improving the Quality of LiDAR Data

As well as removing unrequired points, Global Mapper includes several built-in procedures for recovering points that would otherwise be discarded. The most common and most powerful application of this automatic classification process is the detection and subsequent reclassification of ground points among those that are unclassified. This procedure increases the relative percentage of points that can ultimately be employed in the creation of a DEM resulting in a higher-resolution terrain model.

Other automatic classification procedures include the detection and reclassification of buildings, trees, and utility cables, which is the first step in the feature extraction process.

Creating a Digital Elevation Model

In order to perform virtually all 3D analysis procedures, a LiDAR point cloud will need to be gridded. In this context, gridding describes the process whereby the value associated with each point in an array (typically an elevation value) is used as the basis for generating a solid 3D model. This model can either represent bare earth (a Digital Terrain Model) or an above-ground surface such as a forest canopy (a Digital Surface Model). The distinction between the two is derived from the filtering and selection of the points that are used to generate the surface.

For most LiDAR users, the primary objective is the generation of a DTM, which is the platform for a wide variety of terrain analysis workflows. Without straying too far off the prescribed path (yet another transportation reference), Global Mapper offers an extensive collection of terrain analysis tools, including volume calculation; cut and fill optimization; contour generation; watershed delineation; and line of sight analysis.

LiDAR data and DEM

Feature Extraction

The increased availability of higher density point cloud data has paved the way (OK, I’ll stop now) for a new LiDAR processing discipline. The analysis of patterns in the geometric structure of adjacent points can result in the delineation of building models, represented as three-dimensional polygons; power lines or above-ground utility cables, represented as three-dimensional lines; or tree points, derived from the collective structure of points classified as high vegetation. Global Mapper’s vector extraction tools also include a custom extraction option where 3D lines and polygons can be generated by following a series of profile views that are perpendicular to a predefined path. This tool can be used to create a precise three-dimensional model of any elongated structure, such as a curb along the edge of a street.

Next Steps

The impetus behind this article was to address some typical applications for LiDAR data without delving too deeply into the technical considerations or step-by-step instructions. That said, if you are sufficiently intrigued and are ready to move to the next level, you will need software in order to utilize your LiDAR data. Global Mapper has supported the import and display of LiDAR data since before the format became widely available and each subsequent release has introduced new functionality for effectively managing and processing the data.

Several years ago, Blue Marble introduced an optional module for Global Mapper to address the demand for ever more powerful LiDAR processing tools. If you are interested in the aforementioned automatic reclassification and extraction tools, you should certainly give the LiDAR Module a try.

If you are new to Global Mapper, both the base software and the LiDAR Module can be evaluated free of charge for two weeks.

Webinar Series: LiDAR Processing in Global Mapper

We are releasing a series of short webcasts exploring the use of LiDAR data in Global Mapper and the accompanying LiDAR Module. Beginning with an introduction to the structure and characteristics of LiDAR data, each video will be approximately 20-minutes in length and will cover a specific theme or topic. To receive notification of the availability of these and other Blue Marble video presentations, be sure to subscribe to our YouTube channel or follow us on Twitter.

This is the first video of the LiDAR Processing in Global Mapper series:

 


David McKittrick is a Senior Application Specialist at Blue Marble Geographics in Hallowell, Maine.  A graduate of the University of Ulster in Northern Ireland, McKittrick has spent over 25 years in the field of GIS and mapping, focusing on the application and implementation spatial technology. McKittrick has designed and delivered hundreds of GIS training classes, seminars, and presentations and has authored dozens of articles and papers for a variety industry and trade publications.