David Doyle, Geodesist

Dave Doyle, Geodesist, joined the National Geodetic Survey in 1972, and held the position of chief geodetic surveyor at his retirement in January, 2013. He was responsible for the development, technical design and management of plans and programs that enhance the United States National Spatial Reference System. Mr. Doyle began his career as a geodetic surveyor in the U.S. Army in 1967. From 1970 to 1972 he worked for a private surveying company near Washington D.C. where he was responsible for completing boundary, topographic and engineering surveys while he pursued undergraduate studies in geodesy and mathematics at the George Washington University. During his time at NGS his experiences included all phases of geodetic triangulation, astronomic positioning, leveling, GPS data collection, data analysis, datum transformations, network adjustments, and data publication. He has also provided technical support to various countries for the modernization of national and regional geodetic reference systems in Caribbean and Central America, Africa, and the Pacific. Mr. Doyle’s activities also include 33 articles in national and local surveying publications and he has conducted more than 380 workshops and seminars detailing the numerous aspects of geodesy and the National Spatial Reference System. Mr. Doyle is a past president of the American Association for Geodetic Surveying, a Fellow member of the American Congress on Surveying and Mapping, a charter member of the Geographic and Land Information Society, and he has served on the U.S. delegation to the International Federation of Surveyors. Mr. Doyle is also an active member of the District of Columbia, Maryland and Virginia surveyors’ professional associations and was awarded the 2008 Surveyor of the Year by the Maryland Society of Surveyors.

David's Courses

Fundamentals of Geodesy Part I – Introduction

The science of Geodesy is at the heart of all accurate horizontal and vertical positioning. The development of the NAVSTAR Global Positioning System (GPS) and other space-based positioning and global navigation satellite systems (GNSS) provides us with capacity to locate virtually anything, anywhere at any time to within a few centimeters. Understanding the basic principles of physical and geometric geodesy is vital to being able to accurately describe the vast amounts of high accuracy positioning information that is being collected and shared all around the world. This course will review the historical development of our knowledge of the size and shape of the Earth and the fundamental design of horizontal and vertical datums and their realization.

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Fundamentals of Geodesy Part II – Classical Horizontal Datums

Accurate descriptions of horizontal positions are defined with respect to a reference surface or datum. This course will describe the general architecture of a horizontal/geometric datum and how that process has evolved since the early nineteenth century, including the evolution of the agencies now represented by the National Geodetic Survey (NGS), the process of triangulation and space-based positioning.

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Fundamentals of Geodesy Part III – Contemporary Geometric Datums 1

Developments in space-based positioning, especially the NAVSTAR Global Positioning System (GPS) have revolutionized the ability to capture high accuracy positions anywhere in the world. The impact on the design and maintenance of classical horizontal datums has been unprecedented in history of geodesy. The transition from locally defined datums to those that are more globally referenced and provide considerably higher positional integrity has been a challenge for national geodetic institutions around the world. This course will outline the various efforts by the National Geodetic Survey to adapt to these changes and provide improved realizations and products and services to support the increasing demands of diverse disciplines.

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Fundamentals of Geodesy Part IV – Contemporary Geometric Datums 2

The demise of the cold war and the development of the internet have vastly expanded international collaboration and partnership in many scientific endeavors. The science of geodesy has benefit immensely from these efforts. Significant advancements in space and terrestrial measurement systems such as the Global Navigation Satellite Systems (GNSS), Very Land Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR) and Doppler Orbitography and Radio Positioning Integrated by Satellite (DORIS), have greatly improved our knowledge of earth orientation parameters including the knowledge of the location of Earth geocenter, Polar Wobble (Chandler Wobble) and tectonic plate velocities. National geodetic surveying and mapping agencies along with government and academic research institutes from across the globe now share vast amounts of positioning information with the International Earth Rotation and Reference System Service (IERS) headquartered in Paris, France. Periodically the IERS releases updated positional and velocity information for the network of stations providing this foundational information. From this network national organizations can ensure that their respective geodetic reference frames are kept up to date and consistent with the most current understanding of the motions of the planet. This class will review the efforts of the IERS and how NGS and the National Geospatial-Intelligence Agency (NGA) ensure the integrity of NAD 83 and WGS 84.

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Fundamentals of Geodesy Part V – Coordinate Systems

Describing the location of a point is a critical part of its geodetic realization. This presentation describes the three general ways to show a point’s coordinate location. These include: Earth-Centered Earth Fixed (ECEF) coordinates, geographic coordinates (latitude, longitude, ellipsoid height) and plane coordinates such as the State Plane and Universal Transverse Mercator grid systems.

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Fundamentals of Geodesy Part VI – Vertical Datums & Geoid Models 1

The need for accurate, consistent and reliable height information is one of the most important set of attributes for any local, regional or national geodetic system. Planning for inundation and flood modeling, ecosystem risk assessment, civil engineering, topographic mapping and charting are vital elements of our national infrastructure. Vertical datums provide the foundation to which all of these activities can be related. This presentation explores the relationship between tidal and geodetic datums and the most general types of heights that are encountered and how they relate to each other. In addition, the presentation reviews how heights are determined and the National Ocean Service (NOS) VDatum transformation tool.

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Fundamentals of Geodesy Part VII – Vertical Datums & Geoid Models 2

The development of a geodetic vertical datum for the United States traces its history to 1877. Since that time the U.S. Coast & Geodetic Survey, now called the National Geodetic Survey has conducted high accuracy leveling across the country including the island areas of Hawaii, American Samoa, Guam, Northern Marians, Puerto Rico and the U.S. Virgin Islands. This presentation will discuss the historical development of those efforts along with the evolution of the computation of increasingly more accurate geoid models to support GPS-derived heights. The class will also briefly discuss some of the limitations of GPS-derived heights.

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Fundamentals of Geodesy Part VIII – Future Datums for the U.S

During 2008, the National Geodetic Survey conducted an in-house study of the ability of the National Spatial Reference System to support the increasing demands for high accuracy positioning services and capabilities. One of the significant conclusions of that effort was that NAD 83 and NAVD 88 (and other island vertical datums) have sufficient deficiencies that will likely make them unable to support the potential for improved positioning technologies in the near future. To meet these challenges NGS has embarked on an effort to replace these datums with a more contemporary reference frame that will bring the United States geometric datum into closer alignment with the International Terrestrial Reference Frame and provide for a vertical datum based on gravity observations instead of geodetic leveling and the reliance on passive geodetic marks (i.e. bench marks). This class will discuss the rational for these changes, the on-going program of Gravity for the Redefinition of the American Vertical Datum (GRAV-D) and the changes in position and heights that will result from these new datums.

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NGS Datasheet Tips

As part of their work, surveyors, engineers and other disciplines use information published on data sheets published by the National Geodetic Survey (NGS). However many have difficulty finding the information they want in these data sheets. In this course former NGS Chief Geodetic Surveyor Dave Doyle, explains the many types of data sheets. He goes through the entire sequence of information and provides many helpful tips so that this course can serve as the “secret decoder ring” for many. In addition, Dave discusses DSWORLD, a program contributed toNGS that all users can access to view control mark locations against a Google Earth backdrop, but to also participate in a crowd sourcing activity that NGS encourages, but which is not widely known, to update mark location information and to add photographs to aid future mark visitors. Copious example data sheets that are discussed in the course are part of the downloadable materials that come with this course.

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