Hans Wierenga is a consulting i-planologist - the IT equivalent of a city planner. He works for the Altran group and is based in Amsterdam. He is one of the two founding authors of the NORA, the business and IT reference architecture which guides the development and business alignment of the IT of all layers of government in the Netherlands. He is a key author of the GEMMA information architecture, in which the principles of the NORA are worked out in detail for all Dutch municipalities.