Did you catch Global Mapper on television over the summer? In an episode of the Travel Channel show, “Expedition Unknown,” the production crew visited Guatemala in search of Mayan Ruins. A team from LiDARUSA, longtime Global Mapper users, were also involved in the project, collecting LiDAR data for the Mirador Basin Project. Using a combination of drones and helicopters, the data was collected and processed, revealing an uncharted Mayan causeway. As you will see in the footage below, Global Mapper was used to classify bare earth and to view the model that was generated.
No need to worry about this brief cameo going to our heads, the “As Seen On TV” people won’t let us use their logo.
Are you an engineer? Did you study linear algebra in college? Perhaps you have an advanced mathematics degree? If so, you might not find this blog helpful. If you’re like many folks in the GIS industry today who did not take a heavy math load in college and are not working as a surveyor or engineer, then this blog hopefully will help you to understand one of the fundamental principles of mapping. Geodesy is that area in GIS that is a bit of a dirty secret in that many people try to avoid it or don’t understand it. Technically it’s the branch of mathematics and science focused on accurately measuring and understanding the size and shape of the earth, its orientation in space, and its gravity field. It is a $100,000 word that even sounds intimidating, but break it down and it will hopefully make sense. It’s the underpinning of all mapping but it can be the most difficult to understand and the most intimidating to the unindoctrinated. I am here to help with my top ten list of geodetic fundamentals, explained in an easy to understand and hopefully easy to remember approach. So let’s dive in to the deep end, shall we?
Number 1: It’s Coordinate “Reference” System not Coordinate System
This is an important point, no pun intended, to remember. The Coordinate Reference System (CRS) is a reference model that packages up everything we need to communicate locations, sizes, and shapes. It is a toolkit that gives us a language to accurately enumerate positions on the earth. Some of the tools in the CRS toolbox are Ellipsoid, Datum, Map Projection, Units, and Origin. A CRS is defined by these concepts, which allows us to talk geodesy. Just remember that we are using a math model to reference the earth. Blue Marble has a tag line: Mind the Gap Between World and Map. That is what we are talking about. Unfortunately there is not a good acronym for these terms. EDPUO does not have a good ring to it. I’ve tried switching them around, nothing works. But you usually need them all to make a CRS.
Number 2: Transform not Convert
When I first started working at Blue Marble, we used to use the phrase “coordinate conversion”. Over the years, we have moved away from that phrase simply because it implies a process that is exact and easily reversible when that is not always the case. When we change coordinate reference systems we are actually transforming the data. We are moving all of the points to a new system and, if we were to reverse that process, we are actually transforming the data again and on some small level those points will not be exactly where they were before. The concept here is that there is much more going on behind the scenes.
Number 3: Three types of Coordinate Reference Systems
There are three main types of CRS that we work with ̶ the Geographic, the Projected, and the Geocentric. Geographic coordinate systems can be thought of as a globe, a whole-earth model. The units are angular like degrees as opposed to feet and are focused on rotation around an axis. This type of system gets us close to the shape of the planet without a lot of distortion. But it is not practical for talking about directions, distances and relative locations. That is why we have the projected systems. Think of the projected systems as taking the round globe and projecting it on to a flat plane. These behave like planar Cartesian systems that allow us to map x and y on a grid in linear units like feet, meters or miles. The third type of system is called geocentric or earth centered/earth fixed (ECEF). This is a model that is based on an origin that is at the center of the planet (the geocenter) as opposed to the surface. Many of these are gravity-based and they were used for GPS satellite technology.
Number 4: The Types of Datum Transformations
Datum Transformations are probably the most difficult concepts for people to understand. Actually, it’s the concept of a datum itself that trips people up. I like to think of the datum as a tie-down point. It is the point that ties a specific location on the globe to your mapping surface. So, if the datum is where we begin a mapping process, envision moving from that point in one direction. We will call that X. Then we turn to a perpendicular direction that we will call Y. If we introduce a change in height, that is Z. So now we take all three position changes (change in X, change in Y, change in Z) and we move them together to arrive at a different reference surface. In order to mathematically move X, Y, and Z together, we use a datum transformation. A simple, linear, three-parameter transformation tries to leave our point in one place and swap out the surface they are on by lining up a new model under it. The simplicity of the shift has tradeoffs in terms of accuracy. If we add more complexity we add more parameters like rotations and scale and we can move into seven, ten, and even 14 parameter shifts. This process is very complex, mathematically speaking, and not easily summed up in a brief blog. But the point (once again, no pun intended) is that we have to transform our data in a precise and accurate manner and this process starts with the datum from which we are transforming.
Number 5: Geoids – Getting Vertical
So many concepts, so little time. OK, so the term geoid literally means Earth model. In today’s geodetic world (seriously, not a pun) we consider geoids in conjunction with vertical datums. Vertical datums add a new dimension to horizontal datums. Think of a horizontal datum as mainly dealing with the x and y, based on an ellipsoid. With a vertical datum we introduce a z value for height. With a vertical datum we introduce ‘up’ and ‘down’. The vertical datums allow us to map mountains, valleys, changes in the terrain, by giving us a good zero height from which we start measuring. Mean Sea Level comes into play when we talk about geoids as well. Geoids are typically models approximating where sea level is supposed to be to create an even more accurate reference for height measurement. They of course have a whole bag of assumptions and challenges to bring to the table as the ocean is an ever moving target. It’s important to remember that when talking about sea level, there are multiple models of it and they aren’t all the same!
Number 6: Not just Where but When is your data?
By this stage, I’ve either confused you even more than you were at the start, or perhapsbe you are beginning to understand some of these concepts a little more so that you have a deeper appreciation of where your data is. Well, I’m sorry but for modern mapping it is no longer just about where, but it is also about when. When is your data? Coordinate reference systems can now also carry a value of when the system was measured; a time stamp if you will. Also known as an epoch. Think of the areas of the earth’s surface that are relatively active (moving) due to tectonic activity. The island of Japan is a great example. After a major earth quake in Japan, the entire island can actually move or change its location. There are now time-dependent transformations available, such as HTDP, to address this challenge. Another way to think of this concept is our friend WGS84 ̶ World Geodetic System 1984. The first iteration of this GPS-measured system was way back in 1984. For our millennial friends, that is ancient history. For today’s mapping, if we are concerned with modern measurement, the original WGS 84 is not going to get it done. It’s been realized (revised) six times over the years; we now use WGS84 (G1762), which was realized 1762 weeks (33 years!) after the original and is now several meters away from positions on surface-based models from that time.
Number 7: Process Assumptions – aka Garbage in Garbage out!
So now you have some of the basic concepts in your list checked off. Now you should be able to look at your mapping data, review these issues and know that, if they are all accounted for, you are all set. Your data is accurate. It is where it is supposed to be and you can move on to more cartographic pursuits such as contour generation and buffering. No, sorry it is not that easy. We cannot assume that the process used to create the data we are working with was executed properly. A common problem in modern mapping is we load in secondary data to our map. Many GIS tools will automatically place that data over the base data. If it appears to line up, we assume it is correct. When we bring in our data, if that data was corrupted by a poor transformation process or mis-labeled geodetically when it comes through that process it will still be bad. We may never know. That is why we always have to be on alert for geodetically corrupted data or processes where assumptions are made.
Number 8: The challenge of that last Meter
Today’s GIS and Survey work often encompasses data in the centimeter level of precision or resolution. Data products like high-resolution LiDAR data with multiple points collected per square meter are common place. Working at high-precision levels requires a great deal of care and persistence. The work is far from complete when the data is collected. There are assumptions to question, data manipulations to understand, and limitations to acknowledge. All of the concepts in our top ten come into play.
Number 9: Metadata, metadata, metadata
One way to help battle garbage in/garbage out is the often overlooked, admittedly boring process of metadata. Metadata is data about the data. It is a key to understanding the CRS involved in our map. Information like coordinate reference system, projections, sources, and assumptions are all important forms of metadata. Mapping folks have been talking about metadata for as long as I can remember. Yet it is still often overlooked. We took delivery of a large, high-resolution, and extremely expensive-to-collect LiDAR data set not too long ago and when we attempted to transform the data we realized there was absolutely no coordinate metadata information. Because it was terrestrial LiDAR and intended to be quite accurate, it used a local CRS, but there was no metadata in the files. An easy fix would have been a text file in the folder directory but that was nowhere to be found either. And this data was collected by a licensed land surveyor. Unacceptable! We all have to do better than that.
Number 10: Education on the Science/ Training on the Software
Let’s remember, whether it’s geography, surveying, geology, physics, ecology, or any number of other disciplines, collectively we are talking about science. One cannot simply become an expert on all facets of applied GIS. One can learn the tools involved but the science of mapping itself is the responsibility of the GIS professional and that science is founded on positioning. Additionally, there are any number of software tools that can be used to create maps. All of those software titles address our top ten list and the question of whether or not they do a good job is up to the GIS professional. We said earlier, garbage in means garbage out. We must all work to stay current on the various tools we use for mapping, and thus by extension geodesy, so that we can understand how those tools address our top ten issues. If we are diligent, we can provide accurate mapping. If we are not, the follies and foils of inaccurate data rest on our shoulders.
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.
How Well Did You Do?
Name the body of water – Gulf of Aqaba
Name the country – Brunei
Name the capital city – Dublin
Name the desert – Gran Desierto de Altar or Sonoran Desert
Name the mountain – Mont Blanc
The Winner of March’s Geo-Challenge Is …
Of those who answered all five correctly, Anthony James of Harris Corporation was the first name pulled from the hat. Anthony will be receiving a complimentary copy of Global Mapper. Congrats!
Product News, User Stories, Events, and a Chance to Win a Copy of Global Mapper Every Month
A lot has happened at Blue Marble since our last missive just a month ago. Those of you who keep up with the latest company happenings are probably aware of the latest update to Global Mapper. The availability of version 19.1, which was officially announced shortly after February’s newsletter, includes several significant new and updated features. This month we formally introduce this version by offering you an opportunity to download a free trial, and by inviting you to view a webinar showcasing the capabilities of this release.
Also this month, we announce our plans for our 25th anniversary Blue Marble User Conferences; we chat with our partners at 4DMapper about the innovative work they are doing with the Global Mapper SDK for data processing and management in the cloud. We also discuss the various licensing options that are available for Global Mapper, and we challenge your geographic proficiency in the Where in the World Geo-Challenge.
When version 19 of Global Mapper was introduced in September of last year, the two major functional enhancements were the introduction of the tabular Attribute Editor and the launch of the Pixels-to-Point™ tool for photogrammetric point cloud creation within the LiDAR Module. The recent release of version 19.1 offers an insight into Blue Marble’s unremitting development process, with significant new functionality having been added to these two components. The Attribute Editor now boasts a powerful multivariate querying tool and the Pixels-to-Points tool offers the option to create a 3D Mesh. If you are already using version 19, this upgrade is complimentary. For everyone else, a free evaluation is available.
The Global Mapper Software Development Kit (SDK) provides an opportunity for developers to incorporate much of the data processing functionality of Global Mapper into a third party platform. This establishes the technical foundation for some innovative products and services, exemplified by 4DMapper, an Australian geospatial technology company that provides an enterprise cloud platform for managing, visualizing, and collaborating on geospatial data. Blue Marble recently teamed up with 4DMapper to produce a video illustrating common workflows in Global Mapper and how they can now be performed in the cloud. We also chatted with them about why they chose the Global Mapper SDK.
These days, it seems you need a license for everything. Want to own a dog? You need a license. Driving somewhere? You need a license for that as well. Want to buy and sell real estate? Yep, another license. Maybe you should just stay home and watch TV. In many countries, you even need a license for that. In each of these situations, a license provides the means to ensure legitimacy and protection against misuse. The same is true with Global Mapper licenses. The revenue from your license purchase ensures that a small company like Blue Marble can continue to develop the software upon which you depend. Thankfully, there are numerous licensing options available to meet the needs of every individual, company, or organization.
Most Global Mapper users are probably familiar with the Path Profile tool and its ability to create a cross-sectional view of the terrain or, if you have the LiDAR Module, of a 3D point cloud. What you might not know, however, is that you can now create series of custom-spaced profile views perpendicular to a defined path and that you can export these profiles as 3D line features. Viewed in the 3D Viewer, these lines offer a unique perspective of the terrain.
If you missed the recent live What’s New in Global Mapper 19.1 webinar, fear not! A recording of this hour-long presentation is now available. Among the capabilities that were showcased in this presentation are:
- The redesigned and consolidated Attribute Editor which now includes the attribute joining and calculating tools
- Multivariate or compound querying incorporating user-defined expressions and functions
- Expanded drag-and-drop window docking
- A new option to create 3D line features from one or more path profile views
- Enhanced 3D Viewer navigation
- The ability to create a 3D mesh, complete with photo realistic textures in the LiDAR Module’s Pixels-to-Points tool
- And much more
Judging by some of the responses that we received for February’s Geo-Challenge, the five locations were somewhat obscure. Congratulations to those of you who successfully identified all five, especially Galešnjak, sometimes referred to as Lover’s Island, in the Adriatic Sea. This month’s winner is Allan Mathewson. Allan will shortly be receiving a complimentary copy of Global Mapper. Click here to see how well you did.
For March, five slightly less challenging locations await your perusal, with another copy of Global Mapper up for grabs.
See complete terms and conditions here.
As we mentioned last month, the Global Mapper training calendar for 2018 has been announced. These classes are already starting to fill up so be sure to register if you want to attend or if you would like to become a Certified Global Mapper User.
This month we have another educational opportunity to announce. In conjunction with the American Association of Geographers (AAG) conference in New Orleans, Blue Marble will be conducting a free workshop covering an introduction to Global Mapper as well as LiDAR processing and terrain analysis. This workshop is scheduled for April 13th from 9:00 a.m. to 12:00 p.m. Registration is required and space is limited. Click below for more information and to register.
Blue Marble will be hosting two user conference meetings in 2018 on opposite sides of the U.S. Henceforth referred to as BMUC West and BMUC East, these day-long events will be held in Los Angeles, California on June 8th and Portland, Maine on September 21st, respectively. Over the years, BMUC has proven to be one of the highlights of our calendar offering a forum for direct interaction with our customers. Further details will be announced in the coming weeks but in the meantime, you can reserve your slot today.
Visit with Blue Marble at the following events:
GeoSmart Asia ’18 & Locate ’18
Adelaide, Australia | April 9 – 11
American Association of Geographers Annual Meeting
New Orleans, LA | April 10 – 14
Commercial UAV Expo Europe
Amsterdam | April 10 – 12
Tampa, FL | April 22 – 25
Maine Municipal Association
Augusta, ME | April 27
AUVSI XPONENTIAL 2018
Denver, CO | April 30 – May 3
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”?!
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.”
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.
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.
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?
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 email@example.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 is Graphics and Content Coordinator 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 graphic design at Maine newspapers, and as a freelance photographer.