Abstract

GPS, Geodesy, and the Ghost in the Machine
Track: Geodesy & Geodetic Control
Author(s): Michael Dennis

GPS has revolutionized geospatial data capture for surveyors and GIS professionals. But this revolution has come at a price: Users unfamiliar with the geodetic computations within their software - the "ghost in the machine" - can unwittingly generate positional errors ranging from inches to miles. This problem persists despite efforts by vendors to streamline and simplify the GPS positioning process. This workshop seeks to shed light on the GPS "black box" by explaining the main geodetic principles and terminology behind GPS; reducing blind reliance on GPS and GIS software; and providing practical information and tools for geospatial professionals. Topics include geodetic and vertical datums, map projections, "ground" coordinate systems, geodetic resources, and documentation (metadata). Examples of positioning errors will be used to illustrate the peril of neglecting geodesy in surveying and GIS applications. So bring your curiosity (and your questions) and together we will purge the ghosts from your machines!

Michael Dennis
Geodetic Analysis, LLC
8775 S. Cluff Ranch Road
Pima , Arizona 85543
United States
Phone: 928-322-0956
E-mail: mld@geodeticanalysis.com