Why do we need a geoid-based datum?
Even though the current vertical datum (CGVD28) is very precise over short distances (e.g., 30 km), it includes significant distortions at the national scale. Its access is only available at benchmarks, which are mostly located in southern Canada. Furthermore, the maintenance of a levelling network is very expensive. Thus, the best alternative to levelling is geoid modelling. A geoid-based datum would be accessible by Global Navigation Satellite Systems (e.g., GPS) at any location across the Canadian territory.
