All posts by Dave Doyle

Fundamentals of Geodesy

Part 1: An Introduction Editor’s note: With this article we start an overview of GeoLearn courses offered by Dave Doyle, former chief geodetic surveyor for the National Geodetic Survey and geodesy editor of xyHt.  GeoLearn (geo-learn.com) is an online education business helping professionals reach mandatory continuing education requirements and sort through everyday work issues. Dave’s...

The deputy director told xyHt that NGA wanted to have a bigger role.

NGA’s Involvement With Our World

Above: The deputy director says that NGA wants to have a bigger role. Editor’s Note: On July 23, xyHt editors Gavin Schrock and Dave Doyle were invited to address an audience of professionals at the headquarters of the federal government’s National Geospatial-Intelligence Agency (NGA) in Springfield, Virginia. While this was a closed-door session held to...

Discussion of Senate Bill 804, SB 804

Editor’s Desk: Silent Sea Changes Two events in the past month are possibly among the most important things to happen to this community in a long time.  Both have come almost unnoticed.   On Friday, March 22, I learned that the governor of Virginia was on the verge of signing Senate Bill 804, SB 804...

Surveyors and Surveying: Fit for Purpose

“Fit for purpose” is a phrase I’m hearing about with increasing frequency. I’d strongly suggest that you, my fellow surveyors, begin to pay attention to it. Here’s why.In the May issue I wrote about a recent situation that occurred in Virginia where two counties had decided to define their common boundary through a “GIS map”...

Feature: A New Datum

Finally: the rationale for a new geometric geodetic reference frame to replace the North American Datum of 1983. In 2008, the NGS released the publication of a ten-year operating plan that, among other things, called for efforts to replace NAD 83 and NAVD 88, the official horizontal and vertical geodetic datums of the United States.  (Note...

Editor’s Desk: Use H, Not Z

During recent correspondence with a surveyor friend who was concerned about a positional difference he had observed at an old triangulation station, he sent me the following information: N = 213674.3282 m, E = 178633.4978 m, Z = 6.989 m.  Where the station is located is irrelevant.   This type of a coordinate description is...