Spatial -

NOAA Datums Videos 2014

Differential correction with NA2011 and the newest epoch of NAD83

See our and Datums Basics and GPS Tutorials for the long-awaited results of months of rigorous testing and peer review

Trimble Positions software has replaced Trimble GPS Analyst in ArcGIS 10.1

ALASKA GPS and GIS users - check out Joel Cusick's Datum and Projections presentation Feb 2013

ArcGIS 10.1 - New and Cool improvements see Presentation from Melita Kennedy, ESRI : Projections and Datums Dec 2012

Home Datums Basics ITRF - International Terrestrial Reference Frame
ITRF - International Terrestrial Reference Frame PDF Print E-mail

This was the first 4-dimensional reference frame in that not only published positions (X,Y and ellipsoid heights) but velocities for control points. It is a global (geocentric) system based on not just GPS data but additional datasets including Very Large Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS). These technologies allow for the incorporation of plate tectonics and the movement of the earth surface by very specific locations. It was created in 1988 by the International Earth Rotation Service (IERS) to support high accuracy positioning and has undergone many updates.

The latest realization is ITRF2008 (International Terrestrial Reference Frame 2008)

External link to more about ITRS