Height Reference System Modernization Natural Resources Canada has decided to improve their height reference system. This is the basis for both mapping and many other societal areas including climate change monitoring and science. Height Reference System Modernization (Height Modernization) is a transformative project at Natural Resources Canada for the development, implementation and promotion of a gravity-based height reference system for Canada. In other words, it is the realization of a new vertical datum for Canada by geoid modelling, rather than by geodetic levelling. This autumn ESA expect to finally launch GOCE, a satellite that will improve the gobal geoid subtantially. And I know that USA has a lot of work to do in this field as well. We'd really like all of North-America to have the same height reference system. Get the juicy geodetic details directly from the horse's mouth.