Tag Archives: datums

CGVD2013, Part 2

Above picture:  This color contour map shows the difference between CGVD2013 and NAVD 88, especially of interest to those who work on projects along the U.S./Canada border. In part 1 of this series in xyHt’s October issue, Canada’s new vertical datum is introduced—CGVD2013— with an overview of past Canadian datums, directions during the current transition...

Canada’s New Vertical Datum: CGVD2013

Geodesy Editor’s Note: The study of Earth’s gravity field is one of the most important aspects of physical geodesy. While seldom mentioned in land surveying text books or discussed at local surveying, mapping, or GIS conferences, it is nonetheless one of the most important issues that geospatial experts deal with on a daily basis.   Changing...