HalfMoon Education Inc. Knowledge Gets You There

Presenter: David R. Doyle

Recording Date:

Recording Location: Fairfax, VA

Type: Downloadable MP3+PDF

Product Code: 16841

Product Number: 20 VAGEODTM 1 30 MPDF CP

State-Specific Continuing Education Info:

This digital product is not available yet, but is available for pre-order. After purchasing, you will be notified when it has been released.


This audio recording is approximately 7.5 hours in length and is available for $269. Please refer to specific state licensing rules or certification requirements to determine if this learning method is eligible for continuing education credit.

How to Use

Downloadable self-study formats are available approximately 5 weeks after the date of the live event. Please allow up to 4 hours to download the audio file. This time varies greatly depending on internet speed.

The downloadable self-study package includes an MP3 format audio recording of a live seminar and a PDF of the manual that was distributed at the seminar. You will be required to download both the audio recording and the manual. The manual contains written materials prepared by the seminar speaker(s).

The audio file contains embedded number codes, which you are required to document and return to HalfMoon if you wish to obtain a certificate of completion for the program. The acceptance of self-administered continuing education activities vary widely between states and professions. Before undertaking any self-study effort, you should review the rules of your licensing/certifying entity.

HalfMoon Education guarantees its products. The self-study products are recorded from a live seminar and there are circumstances where an audio recording is not available. HalfMoon will contact you and issue a full refund if the product you ordered is not available. If you are not happy with a product you receive, you can return the product for a full refund. However, refunds will not be issued if completion certificates are requested.


Registration:                        8:00 - 8:30 am
Morning Session:                8:30 am - 12:30 pm
Lunch (On your own):         12:30 - 1:30 pm
Afternoon Session:             1:30 - 5:00 pm

Fundamentals of Geodetic Datums

   Horizontal datums
      • Geodetic surfaces – ellipsoid and geoid
      • Positioning elements of the National Spatial Reference System (NSRS)
      • Classical horizontal positioning – triangulation and traverse
      • U.S. national horizontal datums – NAD 27 and NAD 83
   Development of satellite positioning systems
      • Foundation of space-based positioning up to GPS/GNSS
      • GPS impact on integrity of NAD 83
      • Relationship of NAD 83 and WGS 84
      • Horizontal datum transformations – NADCON, Molodensky
   Vertical datums
      • Vertical datums definitions – geodetic and tidal
      • U.S. national vertical datums – NGVD 29 and NAVD 88
      • Issues with GPS/GNSS-derived heights
      • Vertical datum transformations - VERTCON

New Geodetic Datums for the United States 2022

   Rational for replacing current geodetic datums
      • Problems with NAD 83 and NAVD 88
      • Introduction to International Terrestrial Reference Frame
      • Adoption of ITRF14 into NSRS
   National geodetic survey plans for new national datums
      • New geometric/geopotential datum definitions
      • Gravity for the Redefinition of the American Vertical Datum (GRAV-D)
      • Computing approximate horizontal and vertical positional differences
      • Importance of positional metadata


David R. Doyle

Base 9 Geodetic Consulting Services, in Silver Spring, MD

Mr. Doyle has been involved in geodetic surveying since 1967. He joined the National Geodetic Survey in 1972 and functioned in numerous positions dealing with national adjustments, datum transformation and outreach to the surveying and geospatial community. Mr. Doyle held the position of chief geodetic surveyor for 12 years prior to his retirement in 2013. He now owns Base 9 Geodetic Services which provides consultation to public and private agencies and companies as well as teaching seminars on the fundamentals of geodesy and the National Spatial Reference System. Mr. Doyle is a past president of the American Association for Geodetic Surveying, and he is an active member of the DC, Maryland and Virginia professional surveyors’ associations. He has published more than 30 technical articles on geodesy and was honored as the recipient of the AAGS 2018 Joseph Dracup Lifetime Achievement award in addition to numerous other service awards from state and national surveying associations.