From above and on the ground in Uganda, surveyors prove the Stanley Plateau Glacier is disappearing
SURVEYING EDUCATION GNSS CONSTRUCTION
Digging Deep
UAVs and ground-penetrating radar are helping investigators uncover long-lost and historic African American cemeteries.
Tropical Glaciers
Along the Uganda-Democratic Republic of Congo border reside the last tropical glaciers. But for how long? Geospatial professionals are trying to figure that out to help save a native culture.
Dislocated
Mapping the country in odd ways–via the sandwich
Scanning the Burj Al Arab
Creating a digital model of one of the world’s most iconic hotels created problems from accurately capturing the architectural curves to working while guests slept.
View from Above
Taking the fore in geospatial advocacy in Washington, D.C.
Maps as Art
Creatively mapping Brooklyn.
Legal Boundaries
Expert witnesses need to explain the “why” in court.
Publisher Shawn Dewees shawn.dewees@xyht.com
Editor-in-Chief Jeff Thoreson jeff.thoreson@xyht.com
Director of Sales and Business Development Chuck Boteler chuck.boteler@xyht.com
Creative Director Ian Sager ian.sager@xyht.com
Accounting and Classifieds Angie Duman angie.duman@xyht.com
Editor, Field Notes Eric Gladhill eric.gladhill@xyht.com
Contributing Writers
Partners and Affiliates
A Journey Through Time Located
Surveying the historic Santa Severa Castle in Italy
LAST YEAR THE MAJESTIC SANTA SEVERA CASTLE, a historical and cultural jewel located on the Tyrrhenian coast north of Rome, became the site of survey using an advanced array of geospatial technologies.
This remarkable site, with a deep heritage dating back to ancient Pyrgi in the 7th century BC, has seen the succession of Etruscans, Romans, Phoenicians, and many others, until it became a German military base during World War II.
To document this unique site, Stonex, a provider of measurement and survey tools headquartered near Milan, Italy, employed a wide range of cutting-edge technologies. Thanks to the combined use of 3D scanners, GNSS, and total stations, the entire area has been mapped with millimetric precision, allowing the creation of a detailed three-dimensional model, both for the interiors and exteriors.
The work on the exterior of the castle was carried out with the SLAM X120GO,
capable of capturing every detail with just two 30-minute scans each thanks to its 120-meter range. Furthermore, due to the use of Ground Control Points (GCPs) for georeferencing and point cloud compensation, an extremely accurate picture of the site was obtained. To complete the external survey, a drone equipped with the XFLY lidar was used, which made it possible to map roofs and areas not visible from the ground.
The interior of the castle, now converted into museum spaces, was surveyed with the SLAM X70GO. With its ability to detect narrow and cramped spaces, such as the stairs of the tower, it proved to be ideal for reconstructing architectural details. The X-Whizz mode, in particular, made it possible to combine the speed of the SLAM survey with the precision of static scans lasting a few seconds, thus obtaining a perfect mix of speed and accuracy.
A further level of detail was achieved with the vSLAM XVS scanner, used to return very high-resolution point clouds of the most delicate environments, such as the early Christian church and the baptistery, where precious frescoes and an ancient baptismal font are preserved.
TOPOGRAPHIC PRECISION AND DATA INTEGRATION
In addition to scanning technologies, the S990+ GNSS receiver and the R180 robotic total station, together with the Cube-a software, played a fundamental role in the topographic survey of the area. Essential data was collected for the framing of the castle and its integration into the surrounding context.
Thanks to Cube-a, points and polylines of elements, such as sidewalks and edges, were acquired very easily, allowing for smooth integration with the generated 3D models.
All the data, from the point clouds to the topographic survey, were imported and merged into the Cube-3d software, where it was possible to proceed with the creation of detailed sections and plans in dxf format.
CONCLUSIONS
In less than a day of work, just two Stonex operators were able to survey the entire area of the Santa Severa Castle thanks to the power of SLAM technology. This solution allowed covering large areas in very short timeframes, while ensuring an extraordinary level of detail. The X-whizz mode of X70GO and the XVS videogrammetric scanner offered top-notch solutions for capturing the most complex and detailed architectural elements.
The project demonstrated that innovative surveying technologies applied to historical heritage can open new perspectives and contribute to the protection and enhancement of iconic places such as Santa Severa Castle.
– Jeff Salmon
Italy’s Santa Severa Castle is one of the most important monuments of historical and archaeological interest on the Tyrrhenian coast north of Rome.
A point cloud from the Stonex scan of Santa Severa Castle.
AI and Geospatial Tech to Help Protect Heritage Sites
MICROSOFT, THE SOFTWARE AND ARTIFICIAL INTELLIGENCE BIGWIG, is joining forces with Planet Labs PBC, one of the world’s best sources of hi-resolution satellite imagery, to help protect heritage sites from the impacts of natural disasters, conflict, and environmental catastrophes. Under the HeritageWatch AI initiative, the two companies will collaborate with Aliph (International alliance for the protection of heritage) and Iconem, the 3D modeling experts from France.
The founding organizations will each provide their expertise, from Microsoft’s AI tools through its AI for Good program, to Planet’s global and daily satellite imagery collected by their large fleet of Earth Observation
satellites, as well as Iconem’s pioneering applications of 3D scans and satellite imagery of the world’s great cultural heritage. Aliph will provide its wide experience in supporting more than 500 cultural heritage projects implemented on the ground in more than 40 countries in conflict.
HeritageWatch AI will be an independent, noncommercial effort dedicated to forecasting and analyzing the short- to long-term risks threatening cultural heritage, particularly those related to climate change and natural disasters. Its headquarters will be based in Paris.
—Marc Delgado, marc.delgado@xyht.com
Global Mapper Pro Advances with Upgrades
NEW VERSION 26.1 OF GLOBAL MAPPER PRO INCLUDES interface changes, point cloud classification updates, fine-tuning for vehicle detection, and more. Global Mapper’s iconic toolbar stack has been refined to include a scripting toolbar and a condensed lidar toolbar, both boasting new tools.
The Lidar QC tool provides users with the ability to adjust utilized GCPs to ensure the most accurate calculations. Also, Pixels to Points now supports three different Color Harmonization methods from openMVG.
Global Mapper Insight and Learning Engine (beta) is a deep learning-powered image analysis toolset. The suite of tools provides trained models for land cover classification, vehicle identification, and building extraction. Fine-tuning allows users to re-train layers of a model to improve the analysis results on specific datasets.
In version 26.1, vehicle detection is now supported in fine-tuning and training, providing users with the ability to use their own truth data to tailor models to their needs. Other updates include improved handling of canceled training data, allowing users to easily use the same experiment name again.
Trimble and GroundProbe Team on Monitoring Portfolio for Mining
TRIMBLE AND GROUNDPROBE, PART OF ORICA DIGITAL SOLUTIONS specializing in real-time solutions for measuring and monitoring geohazards, announced a new collaboration. Instead of working through various suppliers to gain guidance on technology solutions, this joint effort will enable geotechnical mine monitoring customers to purchase a comprehensive slope stability monitoring portfolio from a single point of contact, up to 4,600 meters at eye-safe operation in laser class 1. The IP64 certification ensures that it can be used in harsh environments. RIEGL’s Ultimate lidar technology provides multiple-target capability and valuable data attributes for every measurement.
GroundProbe customers can now easily purchase Trimble monitoring solutions to complement GroundProbe’s range of sensors and software through their GroundProbe sales contact.
Mining operators can simplify sourcing and deployment to execute slope stability programs and take advantage of service and support from GroundProbe, Trimble, and the Trimble distribution channel. Customers will also experience more seamless integrations between Trimble and
Nexys Modular 3D Mapping Solution
NEXYS PRO IS A MODULAR MAPPING AND SURVEYING ECOSYSTEM that allows users to quickly capture highly accurate, colorized, real-time 3D point clouds in complex, dangerous, or inhospitable environments like those in the mining, AEC, and geospatial industries.
Proprietary autonomy algorithms, coupled with SLAM-based lidar scanning technology deliver survey-grade results without a pilot—even
GroundProbe sensors and software to enable smooth data flow.
Incorporating the necessary mine monitoring sensors into one environment helps professionals visualize a more complete picture of site conditions to improve decision-making on slope stability risks and site safety.
in GPS-denied, hazardous, and unilluminated environments. Start with mapping only, then upgrade to full autonomy when you need it.
The Nexys Ecosystem of accessories enables it to be handheld, carried in a backpack, mounted to a vehicle, piloted on an aerial robot, or using AL4 volumetric exploration, it can autonomously navigate aerial and groundbased robots.
GNSS Signals Reach the MOON
WE’RE OVER THE MOON WITH THE NEWS THAT REVEALED THAT SIGNALS from the Global Navigation Satellite System (GNSS) can be received and tracked on the Earth’s only natural satellite.
According to NASA and the Italian Space Agency, Earth-based navigation signals from the GPS and Galileo Systems can reach the moon’s surface as demonstrated by the Lunar GNSS Receiver Experiment (LuGRE) project. LuGRE’s payload was able to acquire and track GNSS radio signals on the moon which can be used for positioning, navigation, and timing measurements.
“On Earth we can use GNSS signals to navigate in everything from smartphones to airplanes,” said Kevin Coggins, deputy associate administrator for NASA’s SCaN (Space Communications and Navigation) Program. “Now, LuGRE shows us that we can successfully acquire and track GNSS signals at the moon. This is a very exciting discovery for lunar navigation, and we hope to leverage this capability for future missions.”
The LuGRE payload achieved a navigation fix at approximately 225,000 miles from Earth, indicating the possibility of using GNSS signals for navigation in space between Earth and the moon, or even to would-be space expeditions to Mars.
—Marc Delgado, marc.delgado@xyht.com
Ghost Fleet Hunting from Space
TO AVOID SANCTIONS ON ITS OIL EXPORTS, Russia has acquired a fleet of tankers reportedly to illegally transport its shipments. This so-called “ghost fleet” or “shadow fleet” is comprised of aging tankers which were, if not actually diverted from the scrapyard queue, then certainly high on the list for decommissioning.
These dilapidated tankers pose a threat beyond sanctions-busting. Their decrepit state poses the potential for environmental disasters such as oil spills and “hazard to shipping” incidents when they develop leaks and/or are abandoned. What’s more, ships in this ghost fleet are suspected in two undersea cable cutting incidents in the Gulf of Finland.
To evade detection, these ships either disable their Automatic Identification System (AIS) or spoof the AIS signals to conceal their actual locations.
Locating these ships to monitor and enforce compliance with sanctions and environmental regulations is a challenge that has been taken up by the Norwegian Space Agency (NOSA).
Recently, teaming with Space Flight Laboratory (SFL), NOSA has successfully launched and deployed Norway’s NorSat-4 maritime monitoring microsatellite. The seventh spacecraft developed for NOSA by SFL, NorSat-4 carries a fifth-generation AIS ship tracking receiver and a first-of-itskind low-light imaging camera.
The low-light optical camera expands the Norwegian Coastal Administration’s ability to detect and track vessels in its Arctic territorial waters by supplementing the AIS receiver aboard the satellite. Safran Reosc of France built the camera under contract with the Norwegian Defense Research Establishment to optically detect vessels longer than 30 meters in Arctic darkness.
“NorSat-4 maintains Norway’s leadership in space-based maritime situational awareness with a cost-effective small satellite program,” said SFL director Dr. Robert E. Zee. “The addition of the low-light imaging camera on this mission continues the NOSA tradition of testing cutting-edge onboard technology.”
—Jeff Salmon
WingtraOne Gen II Launches with 61 MP Camera
WINGTRAONE GEN II INCORPORATES A 61 MP CAMERA allowing it to fly higher than drones limited to 20 MP cameras, so users can capture more ground and more detail with every picture and a larger area per flight.
With an onboard high-precision PPK GNSS receiver users no longer need to lay out ground control points (GCPs). Use as few as three checkpoints to verify your map quality. Faster data collection and expanded coverage means fewer people in the field for less time, lowering the man-hour costs associated with data collection.
High-quality optics means users can reconstruct maps reliably, even with lower overlaps. Coupled with a 59-minute flight time, this means more ground covered by the flight line and maximum coverage per flight.
EVENTS
Carlson User Conference
May 6-8
Maysville, KY
Xponential/AUVSI
May 19-22
Houston, TX
CGA Conference: Geography of Digital Twins
May 22-24
Cambridge, MA
GEO Business
June 4-5
London, UK
Hexagon LIVE
June 16-19
Las Vegas, NV
Esri User Conference
July 14-18
San Diego, CA
LP360 User Conference
October 22-24
Huntsville, AL
Trimble Dimensions
November 10-12
Las Vegas, NV
Mapping Palisades and Eaton Fire Burn Areas
LIDAR TECHNOLOGY PLAYED A CRUCIAL ROLE in the successful release of high-resolution lidar data for the Palisades and Eaton Fire burn areas in California. This data, collected by NV5 and utilizing RIEGL's VQ-1560 II and Applanix IMU, is now freely available to the public courtesy of the U.S. Geological Survey (USGS) at 2025 Post-Wildfire Lidar Data for Los Angeles. The data includes a 0.5-meter Digital Elevation Model (DEM) and Digital Surface Model (DSM). The lidar data acquisition was sponsored by ALERTCalifornia.
The data acquisition took place between January 21 and January 22 this year and includes essential information for analyzing the impact of the fires. This data is critical for damage assessment, recovery, and rebuilding efforts, as well as understanding potential hazards such as debris flows and flooding.
The burn zones were flown at 16 points per square meter and will undergo additional processing to fully comply with USGS 3DEP Lidar Base Specification Standards.
This project underscores the importance of advanced lidar technology in supporting recovery and rebuilding efforts after devastating wildfires. By comparing the new data with previous lidar collections from 2023 and 2024, researchers can measure changes in terrain, vegetation density, and burn severity.
This analysis helps quantify fire damage, identify areas at risk, and guide restoration efforts. Additionally, lidar can detect remaining hazards like unstable trees and compromised structures, ensuring safe recovery operations.
Virtual Surveyor Adds Topographic Design Tools
VIRTUAL SURVEYOR HAS ADDED BASIC TOPOGRAPHIC DESIGN tools to Version 10 of its smart drone surveying package, allowing users to design simple terrain changes, such as graded roads, water ponds, and flat building surfaces, on top of their surveys. To accurately visualize these future topographies, Virtual Surveyor has re-organized its software plans around the concept of time.
Virtual Surveyor software has traditionally provided users with an end-to-end workflow to conduct 3D surveys from drone imagery under progressive subscription plans: Valley, Ridge, and Peak. Valley is the free introductory package, while the paid Ridge and Peak products offer increasingly robust capabilities to create 3D survey products from UAV-derived images and lidar data.
MAPPING THE COUNTRY BY SANDWICHES
Sometimes it’s interesting to look at the world a little differently. Maptitude, a mapping software tool and a Geographic Information System, allows users to do just that by viewing, editing, and integrating maps. Here a user created a look at the United States through the eyes of sandwich mongers to show which states have the most searched-for lunchtime delights.
Some of these make perfect sense. Pennsylvania and the Philly cheesesteak; Wisconsin and the grilled cheese; Louisiana and the Po’ Boy. All no brainers.
But Maryland and the shrimp roll? Really? I’m a Marylander and have never searched for a good shrimp roll, but I’m
always on the lookout for a good crab cake sandwich.
Why are Tarheels and Texans searching for a good chicken sandwich? Shouldn’t they be looking for the best barbeque sandwich they can find? And only Vermont and Maine are on the lookout for a quality meatball sub? Isn’t everybody looking for a good meatball sub?
The bland turkey sandwich is prominent in nine random states, including Minnesota, where the quest for turkey interrupts the contiguous quest for grilled cheese that starts with Cheeseheads of the Badger State and continues south through Iowa, Missouri, and Arkansas. Why is the great dairy state of
Minnesota not on board? I guess Lakers can’t do anything their neighbors do, including win a Super Bowl.
I find it odd that the French Dip is the preferred sandwich of South Dakota and Montana. Maybe that goes way back to being part of the territory included in the Louisiana Purchase from France? And what about Alaska and Hawaii being non-sequiturs and liking the egg salad sandwich and avocado toast? (Is that even a legit sandwich?)
While learning what sandwiches are popular in different states may not tell us anything about ourselves, it tells us a lot about our ability to map these days.
– Charles Jeffries
SCANNING THE ICONIC
BURJ AL ARAB
An ambitious 3D scanning project captured one of the world’s unique hotels in detail to help shape its next chapter.
BY NATHAN SAVORY
The Burj Al Arab, a 320-meter-tall showpiece, has defined Dubai’s skyline since 1999. A symbol of luxury and innovation, this iconic 60-floor, 7-star hotel has evolved and grown over its lifetime. However, these renovations left its original 2D floorplans outdated.
The hotel needed accurate 3D plans of the building to better manage maintenance and renovation projects, optimizing the luxury experience for visitors.
PRD Measurement Solutions, a specialist surveying consultancy based in the United Arab Emirates, undertook the task of creating a precise 3D model of the entire, elaborate, structure. The
Burj Al Arab’s unique architecture, combined with strict limitations on when scanning work could be conducted,
presented significant challenges.
The team had to employ a variety of tools, including a 3D laser scanner, to
The project had to be completed in the early hours of the morning to avoid disturbing the hotel's guests.
The Burj Al Arab sits on a manmade island in the Persian Gulf.
create the digital model of the hotel. This documented the landmark’s iconic design and provided precise data to support the future development of this architectural masterpiece.
UNIQUE SURVEYING CHALLENGES
The PRD team was tasked with a complex job: capturing every intricate curve and floor of the Burj Al Arab in 3D. The hotel’s traditional Arabian sail-shaped design posed a challenging surveying environment. Not only is the building devoid of straight lines both internally and externally, but the expansive atrium soars 180-meters high.
traverse around the building. For the internal traversing, the team worked floor by floor using a 3D laser scanner from Leica Geosystems, starting from the ground level and moving upward through the atrium.
This systematic approach helped overcome the setbacks posed by diagonal escalators and winding staircases–ensur-
Adding to the hurdles were hidden stairwells that proved difficult to access, harsh weather conditions, and strict overnight work hours limited to 1 a.m. to 5 a.m. to avoid disrupting the hotel guests. With additional security
clearance protocols, the project required efficiency and precision. This meant meticulous planning and practical hardware to guarantee the high level of accuracy needed under the time constraints, all while maintaining the 7-star reputation of the hotel.
FROM CURVES TO CLARITY
To overcome the complexities of the structure, the surveying team established external control point measurements using GNSS and a closed-loop
ing precise measurements and maintaining alignment across every floor.
While a total station was ideal for some of the external measurements, a 3D laser scanner was deployed to scan the hotel’s interior. Its ability to capture millions of points per second made it possible to thoroughly document each floor of the hotel to RICS tolerances within the tight overnight work schedule.
Due to the time restrictions, the team had to be certain after each setup that all the necessary data had been captured. So, they used cloud-based field software to verify the data collection in real-time, ensuring accuracy and complete coverage before progressing to the next floor.
Despite strict security measures that restricted the team to using a single scanner, they successfully completed the project
The Burj Al Arab, towering at 320 meters, has been a landmark of Dubai’s skyline since 1999.
Cloud-based field software verified data in real-time, ensuring each floor was precisely scanned before moving on.
3D laser scanners captured each curve and detail of the hotel’s lobby.
within just one week–completing almost 600 individual scans over two nights.
TRANSITIONING FROM 2D TO 3D DATA IN BUILDING CAPTURE
Once the data was collected, the raw point cloud data was refined into a 3D model back at the office. For the hotel, transitioning from 2D to 3D representation provides greater detail, improved visualization, and easier collaboration.
Traditionally, the interior designers relied on 2D plans–elevations and
cross-sections–to guide their projects. However, showing them the resulting 3D model proved what they had been missing out on.
Now, much of the hotel staff, including interior designers, managers, and maintenance engineers, can access a clearer, more comprehensive view of the space, enabling them to plan more effectively.
SCANNING THE HEIGHTS
The comparison between the new schematics and the original plans from 1999
revealed just how transformative the scanning process had been. The existing as-built plans were riddled with inaccuracies, including missing floors and incorrect dimensions, the result of limitations in the technology available at the time. The resulting data now allows the hotel staff to visualize the multitude of rooms in extraordinary detail, to milometer accuracy, supporting decision-making and reducing the risk of costly reworks as a result of unnoticed errors.
Thanks to the adoption of 3D laser scanning, the surveying team created a model and associated plans of the Burj Al Arab, capturing every curve and floor with pinpoint accuracy. This scan now stands as a vital tool, offering up-to-date schematics for future renovations and maintenance, celebrating Dubai’s most iconic landmark. ■
Nathan Savory is the regional segment manager for Reality Capture (EM, EMEA, and Asia) at Leica Geosystems (part of Hexagon). He helps organizations utilize laser scanner solutions within an everdeveloping digital ecosystem.
The traditional Arabian sail-shaped design of the hotel posed a challenge
The Burj Al Arab’s expansive 180-meter atrium.
FINDING AND PRESERVING
LOST BLACK CEMETERIES
UAVs and ground-penetrating radar are making the work more successful and efficient
By Karen Sullivan
Aerial UAV mapping and ground-penetrating radar help investigators locate forgotten Black cemeteries.
The garden-inspired settings of many U.S. burial grounds are marked by unique architecture, sculptures, landscaping, and parting sentiments inscribed on tombstones. Few Black cemeteries have received similar adornment.
From the start of slavery in 1619 until just after emancipation in 1863, plantation owners typically set aside marginal plots for burial sites of enslaved people. Black families also faced restrictions on burial locations for roughly a century after the Civil War because local laws supported racial segregation.
Now, communities across the country are rediscovering forgotten and lost Black cemeteries and documenting their history, using technology to map above and below ground. In late 2022, Congress passed the African American Burial Gounds Preservation Act, that will provide resources to locate, document, and preserve these often unmarked or abandoned sites through 2027.
Remote sensing and geographic information system (GIS) technology are aiding efforts to document remnants of burial sites after decades of neglect and often misuse. Drone imagery helps researchers see patterns from above, and ground-penetrating radar detects the location of what is beneath the soil. The data produced by these technologies is layered on GIS maps to show clear evidence of hallowed grounds even when the land is overgrown.
A GARDEN OF GENEALOGY
rediscovering and protecting lost gravesites with the passage of the African American Burial Grounds Preservation Act. The work will give tens of thousands of families a tangible connection to their ancestors, many of whom made contributions that shaped their community’s history and culture.
“Graveyards, burial grounds, and cemeteries not only honor our ancestors, they’re also an important resource for historians and genealogists who want to tell our history,” said U.S. Representative Alma Adams from North Carolina, an advocate for the preservation of Black cemeteries.
The application of advanced technologies means burial sites will remain undisturbed as research teams more sharply define their features. GIS maps provide accurate positioning and documentation, enriched by layers of data from current research and historical records. In this way, the map becomes a collaboration tool for teams restoring neglected sites.
GIS maps are also being used as resources for visitors. At Mount Auburn Cemetery in Cambridge, Massachusetts, visitors can use the Flora Mount Auburn app to take themed tours of the 175-acre grounds. African American heritage is one of the tour themes. The maps and app help visitors find their way around the property and learn about its horticulture and history, which dates back to 1831.
TECHNOLOGY AIDS BURIAL SITE RECOVERY
At C. Leon King High School in Tampa, Florida, officials
The national pattern of disregard for Black burial grounds left most of these cemeteries uncounted, unprotected, and rarely documented on maps. As land ownership changed over the centuries, many Black burial sites were lost to development or neglected and became overgrown. Illegal dumping worsened conditions at many sites. Today, flooding and high winds that are intensifying because of climate change further threaten these fragile sites.
Families and preservation groups have more hope for
Ridgewood Cemetery and its historical marker. Courtesy The Historical Marker Database
announced in 2019 that a search using radar had located 145 coffins in an unmarked gravesite on campus. The tally suggested that even more remains were yet to be found in an area once known as Ridgewood Cemetery.
The New York Times reported that Ridgewood was the burial place for as many as 250 Black residents in the 1940s and 1950s. Investigators tracked land sales to determine how local agencies acquired the cemetery before building the school.
A few months earlier, radar also helped investigators in Tampa locate Zion Cemetery and hundreds more unmarked graves. Zion was the city’s first Black cemetery, and nearly 800
Black residents were buried there during segregation, according to a report by the Tampa Bay Times . Although construction workers dug up three caskets on the site as development of the Robles Park public housing complex began in 1951, the project continued. More recently, researchers overlayed images of the burial plots onto a map of the Robles Park property. This showed that graves were still in place a few steps outside doorways and underneath lawns of housing units. A local restaurant’s warehouse operated on another section of the cemetery.
As investigations continued in Tampa, researchers located eight other Black cemeteries. Similar work began to examine suspected burial sites at Tampa’s MacDill Air Force Base and other sites across the state and the nation.
In Tulsa, Oklahoma, an invoice paid by the city confirmed that at least 18 unnamed victims of the city’s 1921 race massacre were buried at Oaklawn Cemetery, the mayor announced in April 2023. Radar and digital maps helped investigators locate the unmarked graves.
Efforts continue to find the remains of other victims of a mob’s two-day attack in the city’s segregated but prosperous Greenwood neighborhood. An estimated 300 Black people died there. News accounts suggest that some victims may have been buried in mass graves at several locations, including along the railroad tracks and in the Arkansas River.
Ground-penetrating radar helped investigators in Tampa locate Zion Cemetery and hundreds more unmarked graves in a developed neighborhood.
Members of the East End Cemetery Collaboratory worked to map and gather the information and images on this map of Barton Heights Cemeteries in Richmond, Virginia. The map is intended as a resource for descendants and visitors to navigate the rich history of those buried there.
At Mount Auburn Cemetery in Cambridge, Massachusetts, visitors can tour African American gravesites guided by a map developed by Blue Raster.
TENS OF THOUSANDS OF GRAVES IN FOCUS
While the state of Virginia paid for the care of Confederate cemeteries, it withheld the same benefits for burial sites of the formerly enslaved until 2017, according to an article published in the International Journal of Historical Archaeology . Access to family genealogy and local Black history was more limited there as a result.
One of the largest preservation efforts for Black burial sites focuses on two cemeteries in and adjoining the city of Richmond. Tens of thousands of now mostly unmarked graves are scattered across more than 76 acres at East End and Evergreen Cemeteries.
Two neighboring Black burial places that also suffered from neglect—the 30-acre Oakwood Cemetery (1917) and the four-acre Colored Paupers Cemetery (1896)—added to the urgency of preservation work.
A research team used GIS technology with drones to find burial sites at the 16-acre East End Cemetery and the Colored Paupers Cemetery. East End Cemetery is considered one of the area’s most significant memorial gardens because its opening in 1897 gave Black mourners a dignified place to grieve and remember those who died. Among those interred were doctors, ministers, and bankers. Many were born enslaved. When researchers processed the drone-captured images of East End Cemetery using GIS technology, they detected oblong depressions in the soil. With this analysis, they were able to document and map 8,000 graves. Volunteers separately located 3,300 marked graves. A map now identifies the location of each.
By recording the dates on grave markers, researchers offered evidence of the chronological development of East End Cemetery section by section. The team followed the same processes to confirm gravesites in the Colored Paupers Cemetery.
As the preservation of Black burial grounds progresses across the U.S., crucial pieces of the puzzle are emerging to further our understanding of the nation’s history. Advances in technology are making the work more successful and efficient. ■
Karen Sullivan writes about technology’s power to integrate the digital and physical worlds and how that integration is reshaping modern life and business operations. She also examines technology’s role in helping individuals and organizations address some of the most complex challenges of our time. This article originally appeared at Esri Blog.
Karen Sullivan
Project Pressure’s Klaus Thymann works with Kule Jocknus Bwabu Solomon, Muhindo Rogers of Uganda Wildlife Authority and glaciologist Heïdi Sevestre to set up precision points for photogrammetry survey.
RWENZORI A RECKONING WITH THE
3D model maps of disappearing tropical glaciers reveal a stark warning for the cultural future of Uganda’s Bakonzo people
By Mary Jo Wagner Photography courtesy of Project Pressure
matic landscapes, the mountains have three main peaks, Mt. Stanley, Mt. Baker, and Mt. Speke. Mt. Stanley, with its highest peak at 5,109 meters (16,761 feet), is Africa’s third tallest mountain, with snowcapped summits and glaciers remarkably close to the equator. The ice on Rwenzori is the highest and most permanent source of the River Nile and constitutes significant water catchment areas in Uganda—relied upon by five million people, including the Bakonzo people.
The Bakonzo, who live at the foot of the mountain range, hold deep spiritual beliefs that are intricately connected to the natural landscape, particularly the snow-capped peaks. For centuries, a core belief for Bakonzo is that their gods, Kithasamba and Nyabibuya, reside in the ice of Rwenzori, a house that has been melting away. In fact, both Mt. Speke and Mt. Baker have both lost their glaciers––Mt. Baker’s loss was confirmed in 2022. Only Mt. Stanley’s glacier remains.
RWENZORI
Nestled on the border between Uganda and the Democratic Republic of Congo, the Rwenzori Mountains—a UNESCO World Heritage site—are home to some of the world’s last tropical glaciers, masses of ice that the U.N. predicts will all disappear by 2050 if current rates of warming continue.
One of Earth’s most remote and dra-
Knowing the glacial retreat would continue on Mt. Stanley as well, Project Pressure, a climate charity, led a groundbreaking expedition in collaboration with UNESCO and the Uganda Wildlife Authority (UWA) to the Rwenzori. The goal was to survey all three mountains to both create the first-ever 3D model of Mt. Stanley’s glaciers and install long-term monitoring equipment. The team returned with critical mapping data, scientific measurements, comparative imagery, and a stark warning about the future.
AN EXPEDITION OF FIRSTS
Leading this expedition was Project Pressure’s director Klaus Thymann, a Danish explorer, environmental scientist, and award-winning photographer who has led expeditions since 2012 to the Rwenzori Mountains to track the demise of the tropical glaciers.
“In a world where the impact of climate change is not uniformly distributed, acquiring data on glacier recession in equatorial regions has become paramount,” says Thymann. “This is invaluable for comprehending local warming trends and their consequences to help local communities adapt.”
The 2024 expedition was designed to not only produce a 3D model of the last remaining glacier on the Stanley Plateau to visually preserve the historic record of the ice and its retreat over time, it would also install time-lapse cameras to allow local people to monitor change. Building on data from Thymann’s expeditions in 2012, 2020, 2022, and decades-long glaciological work, the 2024 mapping project would represent the most comprehensive record of the region’s glacial decline.
Key to creating the 3D photogrammetric model was a multi-source solution of geospatial technologies, including GNSS positioning, ground penetrating radar, and an unmanned aerial system.
Once on the mountain, the team drilled 10 orange and green vinyl survey targets into the ice at pre-determined locations. Centered on each target, they used a Trimble Catalyst DA-2 receiv-
The altitude data from Project Pressure’s 3D model of Mt. Stanley indicates the average melting point has reached the top of the glacier.
er, an Android smartphone running Trimble’s TerraFlex field software, and the Catalyst GNSS positioning service to collect a precise location. The small, lightweight, and easy-to-use survey technologies enabled the crew to be nimble without sacrificing accuracy. The GNSS measurements would provide the foundational data to underpin the entire 3D photogrammetry model.
After surveying the targets, Thymann and his team conducted a drone
survey over Mt. Stanley, capturing more than 850 raw images, including the geolocation points, ensuring the model’s spatial accuracy.
In another expedition first, glaciologist Dr. Heïdi Sevestre conducted ground-penetrating radar (GPR) surveys of the the Stanley Plateau’s ice and bedrock to capture data on depth.
THE BLACK AND WHITE OF GLACIAL DECLINE
With a mix of data processing solutions from Pix4D and Trimble, the team combined a drone survey from 2020 with the GNSS data, drone imagery, and GPR survey data from 2024 to create the historic, centimeter-accuracy 3D model of the glacial retreat on Mt. Stanley. Complete with the glacial depths recorded by the GPR, the model provides texture details and exact elevations for the entire mountain, the ice thickness––some depths of 50 meters were recorded––and the glacial recession over four years.
The Project Pressure team confirmed that the glaciers on Mt. Baker and Mt. Speke have now disappeared, while the surface of the Stanley Plateau Glacier has decreased by 29.5 percent since 2020, and it’s dropped eight meters by the side. The upper regions of Mt. Stanley are still glaciated but it’s undergoing severe fragmentation, and the ice is melting at
Glaciologist Heïdi Sevestre carries Trimble Catalyst in her pack as she operates the ground penetrating radar.
Project Pressure’s data from Mt. Stanley’s glacier reveals a loss in surface area of 29.5 percent between 2020 and 2024.
The 2024 Project Pressure and Uganda Wildlife Authority expedition team at base in Nyakalengija.
alarming rates. Thymann predicts it will likely disappear in our lifetime.
“Seeing the surface area reduction of nearly 30 percent in four years was shocking and much more drastic than we thought,” says Thymann. “The future is bleak.”
Beyond the science, the loss is deeply cultural. For the Bakonzo people, the glaciers’ disappearance signals not just an environmental crisis, but the erosion of an irreplaceable cultural heritage.
“The Bakonzo people, who live among the mountains, are strong people who believe that the mountain is a very important aspect of their life,” says Alfred Masereka, an ecological monitoring and research ranger with the UWA. “The disappearance of the ice is bad news because it means our gods are being destroyed.”
The first-ever model not only clearly shows how much glacial ice is left on the range, it gives local teams a foun -
dation for comparative analysis as they continue to monitor the Stanley Plateau.
Project Pressure is now training and equipping local teams to collect data independently.
“The idea is that the local people, in collaboration with the UWA, collect the data,” says Thymann. That could help inform adaptation, particularly when it
comes to water security and storage.
As the ice retreats, Project Pressure will continue to work with the UWA to improve glacial estimates, create mitigating strategies, and expand local capacity for ongoing research and surveyance.
“Without data, you cannot make informed decisions,” says Masereka. “But now this research will help us make decisions from an informed point of view.” ■
Mary Jo Wagner has covered geospatial technology for more than 30 years, writing about remote sensing, GIS, GNSS, surveying, aerial photography, and lidar among other topics. She has written about myriad sectors including environment, government, forestry, utilities, telcos, archeology, transportation, agriculture, military, retail, mining, oil and gas, emergency response, and construction.
Klaus Thymann’s innovative combination of aerial photogrammetry and ground-penetrating radar created a data-led 3D model of Mt. Stanley.
The Rwenzori Mountains once held glaciers on three peaks, but climate change has led to massive glacier loss. The largest glacier is the Stanley Plateau glaciers, here viewed from the side.
MAPPS Is Leading Geospatial Advocacy Efforts in Washington, D.C.
BY BRIAN RABER
MAPPS is the preeminent national association of firms involved in many aspects and benefits of the geospatial field in the United States. A cornerstone of MAPPS is being fully engaged in a non-partisan manner with the legislative process on issues that directly impact its membership and the geospatial profession.
This article summarizes several long-standing and highly effective MAPPS programs which demonstrate the associations’ dedication to Democracy in Action, public and private partnerships, and geospatial political advocacy. The programs below allow MAPPS members to engage in the political process by making their collected voices heard on Capitol Hill and with federal agencies:
• Legislative Affairs Committee (LAC),
• Federal Programs Conference (FPC),
• Capitol Hill Day
• Political Action Committee (PAC).
MAPPS incoming president Renee Walmsley says, “MAPPS advocacy activities provide members current information on our federal agency partners as well as opportunities to engage in legislative action for our geospatial profession.”
LEGISLATIVE AFFAIRS COMMITTEE (LAC)
The LAC is comprised of interested MAPPS members who desire to be active in the political process for the benefit of the entire membership and geospatial community. The committee is guided by a board-appointed chairperson working closely with the MAPPS government affairs and advocacy firm, board of directors, and membership on legislative priorities. The committee works very closely with the MAPPS federal agency liaisons who have direct contact with selected federal agencies on behalf of the membership and board.
The LAC activities are primarily focused on national geospatial public policy and legislation that impacts membership and federal agencies. Increasing the impact and reach of MAPPS is accomplished by collaborating with other geospatial and industry associations on issues of mutual benefits.
Each year the LAC reviews the existing and upcoming federal programs as well as related legislation that is of interest to MAPPS members. It then recommends to the board an agenda, strategies, and priorities for taking specific action on any given issue.
FEDERAL AGENCY LIAISONS
MAPPS has had standing committees with federal agencies since 2003. These federal agency liaison committees allow for a dialog between the private sector and their government
partners. Meetings generally take place two times per year, including at the Federal Programs Conference in March. Presentations and notes from agency meetings are all posted in the appropriate liaison group on the MAPPS website. Readers of xyHt can view articles published over the past few years about the agency liaisons.
FEDERAL PROGRAMS CONFERENCE (FPC)
The FPC is an annual event in Washington, D.C., featuring education sessions, federal agencies briefings on programs, budgets, and requirements for geospatial data, products, and services. This is a valuable meeting for any firm interested in working with the federal government. A significant part of the FPC is preparing membership to be effective on Capitol Hill advocating before Congress and special sub-committees that may have oversight on a particular issue or agency.
MAPPS president Kelly Francis of Aero-Graphics says, “Without the political advocacy conducted by MAPPS, our firm would not have the insight and understanding necessary to compete in the federal marketplace.”
CAPITOL HILL DAY
The day following the FPC, MAPPS members unite on Capitol Hill participating in the democratic process by visiting their state congressional delegations. These educational and advocacy meetings discuss legislation and policy that serve the nation, benefit geospatial firms, and impact local communities.
The MAPPS LAC, board, and members are extremely knowledgeable about the benefits of innovative geospatial solutions and data, upcoming legislation, and agency funding requests, which become the basis for discussions with elected officials. Examples of the 2025 Hill Day topics are summarized below. These are very specific “asks” that MAPPS members discuss with congressional leaders to drive funding and program support.
• MAPPS supports fully funding the U.S. Geological Survey (USGS) National Geospatial Program (NGP) $94,715,000 in for both FY25 and FY26 in order for Core Science Systems to realize the numerous benefits of the 3D Elevation Program (3DEP), and the 3D Hydrography Program (3DHP)
in order to fully integrate hydrography, elevation, and other data from The National Map in a single 3D data model.
• MAPPS respectfully request $684 million to be appropriated to the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service geospatial programs for FY 25 and FY 26 as a continuation of the FY 24 appropriated funding. Specifically, the Office for Coastal Management, the Office of Coast Survey, and the National Geodetic Survey all work with the private sector to perform key legislative mandates that include: many geospatial programs and activities required to meet the objectives of the Coastal Zone Management Act (CZMA) of 1972 and Integrated Coastal and Ocean Observation System Act of 2009.
• MAPPS supports The U.S. Department of Agriculture’s (USDA) Farm Production and Conservation FY 2025 request of $2.63 billion in discretionary funding to focus on domestic agricultural issues and includes the Farm Service Agency, the Risk Management Agency, the Natural Resources Conservation Service, and the FPAC Business Center. FPAC’s Business Center administers the Preservation of Infrastructure and Natural Ecosystems aerial imagery and geospatial-related contracts that comply with: Farm Bill (Agricultural Improvement Act of 2018); Geospatial Data Act of 2018; Clinger-Cohen Act of 1996; Federal Land Policy and Management Act; Homeland Security Presidential Directive-7 (HSPD-7); and the National Infrastructure Protection Plan.
POLITICAL ACTION COMMITTEE (PAC)
For more than three decades, MAPPS has effectively utilized its Political Action Committee to strengthen congressional relationships, political influence, and educating elected officials. The MAPPS PAC regulated by the Federal Election Commission, is a legal, non-partisan, ethical, and professional way for individuals from member firms to engage in our great political process.
Each year, MAPPS makes meaningful contributions to congressional members who are instrumental in helping geospatial legislation and programs advance through the approval process.
MAKE YOUR VOICE HEARD TODAY
MAPPS and its membership are instrumental advocating for geospatial programs by implementing the internal political action strategies and programs mentioned above. Whether a member firm is a prime federal contractor or subcontractor, small or large business, focused on federal or commercial markets, data provider, or technology developer, being involved in MAPPS legislative affairs is good for your firm’s business goals and the geospatial community. Use the QR Code to join MAPPS and be part of the growing geospatial voice on Capitol Hill. ■
Brian Raber is MAPPS past president and a retired geospatial executive.
Hijacking Cartography
Artist Ed Fairburn loves collecting all sorts of antique ephemera, but he has a particular soft spot for maps, which he uses as a canvas to express his art. For example, in this ink work over a map of Brooklyn (based on Cram’s 1894 Universal Atlas), Fairburn draws a human face along lines of roads, rivers and other map details–while carefully preserving the original character and functionality of the map. He calls this “hijacking cartography.”
“I’ve always enjoyed drawing portraits, translating the shapes of the human form under different light conditions into ink on paper, especially through a process of cross hatching,” he says. “I think this integrates well with the visual language of maps.”
Fairburn describes his technique as topopointillism or a meeting of topography and pointillism. “The defining aspect of pointillism is the merging of the marks to create a larger image–one which would
typically become clearer when viewed from further away.”
Last year, two of his creations were included in the box set of Mind Games: The Ultimate Collection, a special edition re-release of John Lennon’s 1973 album. Tucked inside the special album box are two 46-inch square hand-drawn portraits of Lennon and Yoko Ono, which Fairburn superimposed on vintage maps of Liverpool and Tokyo, the cities where each artist comes from, respectively.
The portraits of the two singers, the largest that Fairburn has ever made, were commissioned in 2023 by the Lennon Estate. The album set won Best Boxed or Special Limited-Edition Package at the 2025 GRAMMYs. “I’m most proud of these two works,” he says. ■
Check out Fairburn’s artwork at www.edfairburn.com
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Several years ago, Simon Sinek gave a TED Talk on marketing—a business, services, products, even ideas and beliefs. He used several real-life examples including the success of Apple, the achievements of the Wright brothers, and the beliefs of Dr. Martin Luther King. The video, now somewhat dated, is still available on TED Talks and the principles Sinek laid out are timeless.
Although his talk was focused on business success and inspiring leaders, the message, “start with why,” is easily transferable to winning in court as an expert. Since the essence of expert witness testimony is opinion-based, it is crucial to that testimony to have the ability of explain the “why” of your opinion. As Sinek reiterated in his talk, people do not buy “what” you do or “how” you do it—they buy the “why.” This will be true in court as well.
For ease of discussion and to eliminate repetition over the respective roles of the trial court judge and the jury in a civil lawsuit, we will assume a court without a jury. This is most likely where you will be anyway, as most boundary disputes are tried without a jury. In such a trial, the judge has the triune role of law giver, equity dispenser, and the trier of the facts (e.g., judge and jury). In essence, the judge is the purchaser of what it is you are trying to sell—your opinion.
In a boundary dispute case, the ultimate issue is the on-the-ground location of the property line between the plaintiff and the defendant. In other words, the established boundaries. To be sure we are all on the same page, a property line is the demarcation of the limits of the respective property
rights (ownership limits) of the parties to the litigation. Most other questions are also working toward that ultimate issue, or they are somewhat irrelevant.
In my experience, most surveyors in court can explain “what” they did and maybe “how” they did it, but rarely can the surveyor explain “why” they did what they did. It is this crucial question that the judge is wanting explained in terms that are reasonable and understandable. When that doesn’t happen, the surveyor loses credibility with the judge, and loss of credibility is the death-nell of the expert’s testimony.
The only way to answer the “why” question in a boundary dispute case is through correct retracement theory. Unfortunately, for the individual and the profession as a whole, correct retracement theory can only be found in case law. It has not been described in any state statute, administrative code, or our so-called standards of practice. These sources only deal with the “what” and “how” questions, and no one is interested in buying the answer to those questions, especially a judge. This sumsup the existential problem facing the future of the land surveying profession—but I digress.
Correct retracement theory starts with the common law professional standard of care, which is universal in American Jurisprudence; what the reasonably prudent practitioner would do in like or similar circumstances. With that standard in mind, the surveyor needs to understand that retracement surveying is an evidentiary exercise, not a math and stakeout problem. Too many surveyors do not grasp this concept.
The criterion for gathering and evaluat-
ing evidence is the “best available” evidence. Of all the evidence available to the retracement surveyor, measurements are always at the bottom of the list and rarely needed to answer the “why” question. When the surveyor’s answer to the “why” question is, “the measurements made me do it,” you’re done, and your credibility is shot.
When the best available evidence has been gathered by the reasonably prudent practitioner then, just as with the role of the jury, it must be sifted, evaluated, and weighed.
In most cases, there is a large preponderance of the evidence that leads to the truth of the matter. That truth is then rubbed up against the “appropriate boundary law principles,” to render a well-reasoned opinion on the question the judge wants answered. Because, ultimately, that is also the question the judge needs to provide the parties—“why.”
Next time around we will take a deep dive into the “appropriate boundary law principles.”
The purpose of this column is to encourage your questions on legal issues that affect the surveying profession. You are invited to send your questions to the editor of xyHt. ■
Jeff Lucas is an attorney and land surveyor in private practice in Birmingham, AL. Jeff is an author, columnist, lecturer, seminar presenter, and continuing education provider. He writes a monthly newsletter, The Lucas Letter, dealing with legal issues and the practice of surveying. More information about Jeff and his continuing education courses can be found at www.lucasandcompany.com
