You have clicked on a URL (web address) persistent identifier (PID) for an element of the ICSM 3D Cadastral Survey Data Model (3DCSDM).
This address does not currently resolve to a published resource.
Do not panic!
While this URL doesn't resolve, it's still legitimate - it identifies something, ensuring unique naming and cross-referencing.
Future publication of the model as a Linked Data resource will be undertaken using a common infrastructure for semantic resources which will likely llow all these links to resolve.