Earl F. Burkholder, PS, PE, F.ASCE, admits to developing an early interest in some of the core topics and concepts that have served him well every day of his professional land surveying career. With his interest in geometry and logic piqued at an early age, he was able to pursue those interests and develop a broader knowledge and skill set that has led to a multidimensional career based on the multidimensional (3D) world.

As Burkholder describes it, “I’ve been interested in geometry and logic ever since my high school geometry class where I was exposed to the theorems of Euclid and the importance of developing conclusions that are consistent with original assumptions coupled with subsequent observations. Little did I know then that surveying would capture my interest and provide such a fascinating career. Over the years I’ve paid lots of attention to the geometry of spatial data models. I find conclusions based on the assumption of a single origin for 3D spatial data coupled with Descartes’ solid geometry equations to be rather remarkable.”

His education and licensing tell only a small part of his story. Burkholder received a BSCE from the University of Michigan including the geodetic engineering option (1973) and then an MSCE from Purdue University focusing on geodesy (1980). He was first licensed in Michigan and later in New York, Minnesota, North Dakota, Nebraska, Oregon and Ohio. He currently holds PE and PS licenses in New Mexico.

POB: Where did you start your professional land surveying career?

Burkholder: I began working as a draftsman for Gould Engineering, Inc. of Flint, Michigan in 1968 and worked part-time for James Wilkins Associates of Harrisonburg, Virginia during 1969/70 while enrolled at Eastern Mennonite College.

POB: We understand you had an opportunity to “follow the footsteps” of George Washington.

Burkholder: Yes, my part time drafting job with Wilkins & Associates included aggregating metes and bounds descriptions for a client who was purchasing numerous plots in the Blue Ridge Mountains. This was before the era of computer overlays, so we drew various descriptions on vellum and overlaid them on a light table. There were many inconsistencies — seemingly all related to a called line “across Turkey Saddle Gap.” As I recall, the discrepancy was approximately 600 feet.

One day, Mr. Wilkins was researching records in another county and came across an old map that covered land in the adjoining county — split off from the “parent.” That map showed the original line surveyed across “Turkey Saddle Gap.” That original line was run by none other than George Washington.

With that “senior” line fixed, many subsequent pieces of the metes and bounds puzzle fell nicely into place. I’ve been hooked on surveying ever since.

POB: After Eastern Mennonite College, your education set you up for even more adventures.

Burkholder: From there I enrolled in the civil engineering program at the University of Michigan and graduated in 1973 with a BSCE. I worked the next five years in the transmission line engineering division of Commonwealth Associates, Inc. in Jackson, Michigan and had the opportunity to participate in surveying hundreds of miles of high voltage power line projects from New York to Alaska and several international projects — specifically Brazil and Iran.

In the mid 1970s Iran welcomed development expertise from the West. My employer, Commonwealth Associates, Inc., had a contract to design and supervise construction of 1,000 kilometers of high-voltage transmission power line in Iran. Normal engineering procedure at the time was to develop plan/profile documents using photogrammetric mapping techniques. However, getting an aerial mapping camera into the country (much less up in an airplane) proved to be impossible. Consequently, the route survey data were collected on the ground.

An international mapping company from the UK was contracted to collect the data and to generate the plan/profile documents. Colleagues at Commonwealth spent untold hours coordinating logistics and supervising construction of the power line. I did not get a field assignment in Iran, but I was dispatched to London for a week to review quality control practices of the mapping contractor.

It’s important to understand, this was before GPS or the Internet. Survey data were collected electronically and stored on punched paper tapes. The actual plan/profile sheets were computer plotted at the home office in England.

I was duly impressed by their state-of-the-art mapping procedures, and I was able to attest to the contractor’s demonstrated ability to meet a rather demanding schedule. During the week I spent in London, I was permitted one day for personal sightseeing. I used more than half of that day to visit the Greenwich Observatory. Yes, I stood with one foot in each hemisphere to take a photograph — it was time well spent,

POB: Your next step in education took you deeper into your first love and set you up for a deep dive into the “digital revolution” and data models.

Burkholder: I left Commonwealth to attend graduate school at Purdue University where I earned an MS in geodesy in 1980. That started my academic career teaching upper division surveying courses at the Oregon Institute of Technology.

The OIT Surveying Program dates back to the first Associate Degree graduates in 1951, with the baccalaureate program implemented in 1966 as a Bachelor of Technology degree. I had the opportunity in the early 1980s to assist with redesign of the curriculum leading to a BS Surveying degree which was accredited by ABET in 1984 as one of the first two Engineering Related Surveying Programs — Ferris State was the other one.

While there, it was also exciting to participate in the OIT institutional celebration of its 40th Anniversary in 1987 with many alumni returning to campus for a celebration devoted to surveying and the “new” GPS technology.

Since then, OIT has celebrated its 50th Anniversary with another surveying celebration which included erection of an obelisk inscribed with the names of all surveying graduates to date.

I visited the OIT campus recently and chatted with the current Geomatics (Surveying) Professor, Jack Walker. Contrary to the saying, “you can’t go back,” I have reason to believe I could. Professor Walker and others are to be commended for building and sustaining an excellent program. (see OIT Geomatics)

POB: After OIT, you left teaching, but that only led you deeper into your exploration of 3D.

Burkholder: In 1993 I left teaching to become a consulting geodetic engineer. After a subsequent move to Ohio in 1995, I incorporated Global COGO, Inc. and obtained a trademark on BURKORD to cover the design of a 3D database and related coordinate geometry software.

With advent of the digital revolution, GPS, GIS, computers and emergence of spatial data accuracy, the idea was to make a living by capturing and exploiting the value of the third dimension. If my combination of talent and aspiration would have been a bit different, I might have stayed with it.

POB: You may be selling that experience short. It sounds like your moves in and out of academics and professional practice only fanned the flames of your interest and your work in 3D.

Burkholder: Given the opportunity to return to teaching, with Dr. Jim Reilly at New Mexico State University, we ended up in Las Cruces in 1998 where I had the privilege of teaching surveying courses for another 12 years. While teaching at NMSU, and with the benefit of another sabbatical in 2005/2006, I was able to complete the manuscript for a book on 3D spatial data, “The 3D Global Spatial Data Model (GSDM): Foundation of the Spatial Infrastructure” published by CRC Press in 2008.

Since retiring from teaching in 2010, I have continued to promote the GSDM as a model that the surveying profession can use in place of state plane coordinates. At the request of the publisher, a manuscript for a second edition of the 3D book was written, and the second edition was published in 2017 (copyright date 2018). I’m happy to say that the GSDM appears to be compatible with the 2022 datums as being defined by the NGS.

POB: You mention the sabbaticals were important in developing your interest in 3D.

Burkholder: While on sabbatical leave from Oregon Tech during 1990/1991, I spent most of the year at the University of Maine. What drew me there was Dr. Alfred Leick and GPS. While there, I had the opportunity to attend any class I wanted, sit in on faculty meetings, interact with numerous graduate students, practice my computer skills and not have to do homework or take exams — I could do what I wanted. That period, 1990/91, was the most productive year of my life.

I learned a lot from Dr. Leick. One day I summoned up the courage during a five-minute conversation to share with him my aspiration for “modern surveying applications” using GPS. He listened briefly, then said, “Earl, you have it all wrong. You must focus on the 3D Geodetic Model described in chapter 1 of GPS Satellite Surveying.”

That started it all... the first paper coming out of that sabbatical was “Using GPS Results in True 3D Coordinate System.” It was presented at the ASCE GPS Specialty Conference in Sacramento, Calif., September 1991.

POB: You mention the GSDM, can you provide some details of the 3D GSDM?

Burkholder: In addition to the first 3D paper described above, specific details of the GSDM are given in “Definition and Description of a Global Spatial Data Model (GSDM).” Many other papers are listed at www.globalcogo.com/refbyefb.html.

POB: You also had an opportunity to put a lot of your knowledge of 3D into professional practice.

Burkholder: While employed at Oregon’s Institute of Technology, I was asked to serve as Assistant Editor of the ASCE Journal of Surveying Engineering (JSE). My apprenticeship was short lived as the newly named editor was not a member of ASCE. I was next in line. Although not really prepared for those responsibilities, I received lots of assistance from ASCE staff, and many reviewers bent over backwards to help me. In a way it was “trial by fire” as it became my responsibility to shepherd the review of the technical papers presented at the 1988 ASCE Specialty Conference “GPS ’88: Engineering Applications of GPS Satellite Surveying Technology” in Nashville, Tenn. Those papers are printed in three successive issues of the JSE, November 1988, February 1989, and May 1989.

My involvement with ASCE included getting to know Dr. Kurt W. Bauer, executive director of the Southeastern Wisconsin Regional Planning Commission (SEWRPC). Given our parallel interests, I had the opportunity to conduct several studies for SEWPRC — the third one, published in 1997, was “Definition of a 3D Spatial Data Model for Southeastern Wisconsin.” That report proposes adoption and use of an integrated 3D global spatial data model (GSDM) to replace the separate horizontal and vertical datums in their data base.

That recommendation was not adopted, but that recommendation remains relevant because the scope of the GSDM covers the entire world, not just SE Wisconsin.

POB: Can you give us an example?

Burkholder: An early 3D project completed in 1994 consisted of computing the “shadow height” of an obstructing mountain at the proposed site of a NEXRAD radar installation southeast of Tucson, Ariz. The problem to be avoided was “electronic pollution” of the atmosphere at several observatories on the top of Mount Graham by emissions from the proposed NEXRAD facility some 70 miles distant. An interesting account of surveying for the project was published in the November/December 1997 issue of Professional Surveyor (Volume17, Number 8) — “3D Analysis Siting a NEXRAD Weather Radar System.” 

The problem was solved using Earth-centered Earth-fixed (ECEF) coordinates obtained from GPS observations on several control points: on Mt. Graham, on the obstructing mountain and at the proposed site. After the network was appropriately adjusted, the equation for a line in 3D space from the top of Mt. Graham to the obstructing mountain and across the proposed site was computed. The “shadow height” was determined as the perpendicular offset distance (computed on my HP-41 onsite) from that line to various possible locations. It was an interesting assignment. 

POB: What do you see as some of the challenges for 3D?

Burkholder: Perhaps the biggest challenges facing use of an integrated 3D database can be inferred from two COGO Report Cards on the U.S. National Spatial Infrastructure published in 2015 and 2019. Not surprisingly, the digital revolution is identified as the source of those challenges which come under the banner of “disruptive innovation.” 

While many underlying principles of professional practice remain constant for spatial data users in various disciplines, the following issues deserve careful consideration: 

  • Modern measurement systems collect 3D digital spatial data, largely replacing analog methods. 
  • Traditional spatial data models (horizontal/vertical) should be replaced by an integrated model. 
  • Spatial data accuracy with respect to the world at large (network) and spatial data accuracy relative to nearby objects (local) are both important — especially critical for driverless vehicles. 
  • The collection, storage, manipulation, analysis, display and management of spatial data are all part of a “broad” definition of surveying. 

Addressing these challenges means that opportunities for surveyors (both professional and technical) are expanding exponentially. 

POB: Can you take a second to describe the “report cards?”

Burkholder: Information on the COGO report cards can be obtained from http://cogo.pro/Home_Page.html

Briefly, the COGO Report Card is patterned after ASCE’s report card (published every four years) on various categories of the national civil infrastructure — water, energy, transportation, etc. The ASCE report card does not include the spatial data infrastructure. 

The Coalition of Geospatial Organizations (COGO), formed in 2008 by 13 different geospatial professional organizations representing about 170,000 members, published the first spatial data infrastructure report card in 2015.

I had an opportunity to lead a discussion of the COGO report cards at the 2019 Annual Conference of the New Mexico Professional Surveyors on April 13, 2019 — see item XVI at www.tru3d.xyz.

POB: You talked about replacing state plane coordinates, can we return to that?

Burkholder: Starting about 1961, SEWRPC embarked on an ambitious program to put state plane coordinates (SPC) on every section corner in the seven-county region and reliable elevations on nearby benchmarks. The SPC are NAD27 and the elevations are NGVD29. Those two networks support land and engineering surveys, provide the basis for preparation of large scale topographic and cadastral maps, and constitute the foundational elements for the land information and public works management systems created to serve county and municipal governmental units within the region. As such, the “new” datums (NAD83 and NAVD88) offered no tangible benefit to SEWRPC over the already established horizontal and vertical survey control networks in the region. 

Other users within the region, such as the private sector and state and federal users, exerted pressure on SEWRPC to adopt the newer datums. SEWRPC resisted, but acknowledging a level of accommodation to non-SEWRPC users, I was hired to develop bidirectional procedures by which NAD27 and NAD83 values could be transformed. The stipulation was that the quality of transformation should be “better” than NADCON as developed by NGS. That objective was achieved but at the cost of needing different transformation parameters in various parts of the region. 

Following completion of the horizontal project, SEWRPC tackled the vertical transformation challenge. Admittedly, the horizontal project included a bit of “reinventing the wheel.” Therefore, instead of developing independent vertical transformations, we very carefully tested the performance of the NGS VERTCON program and documented circumstances under which the NGS program, VERTCON, could be beneficially used. A comprehensive simultaneous least squares adjustment of the NGVD 29 level loops with the SEWRPC region confirmed the quality of the previous sequential vertical adjustments that had been performed over the years, and the corresponding VERTCON results were very compatible. 

Being intrigued by the possibility of an integrated 3D network and following completion of the previous two projects (horizontal and vertical), Dr. Bauer and the SEWRPC commissioned a study to provide specificity to the hypothesis that two existing data bases could be replaced by one integrated 3D data base. That 3D report was published at about the same time as Dr. Bauer’s retirement as executive director of SEWRPC. Although not implemented, the report stands as an example of what could be done and is available at: http://www.sewrpc.org/SEWRPCFiles/Publications/ppr/definition_three-dimensional_spatial_data_model_for_wi.pdf

Earl F. Burkholder, PS, PE, F.ASCEEarl F. Burkholder, PS, PE, F.ASCE, is president of Global COGO Inc. in Las Cruces, N.M. His early interests in geometry and logic have led him into a rich surveying career that has included significant work in the 3D Global Spatial Data Model. His work is widely published and he has been recognized by numerous awards, including Oregon Surveyor of the Year. He can be reached at eburk@globalcogo.com.