Time granularity. Behind everything simple is a huge tail of complicated.

International audienceWhen investigating the evolution of historic architecture, and putting together various pieces of information (each with its specific characteristics in terms of precision, scope and reliability), time points and intervals the analyst will identify are often inconsistent in terms of granularity. Simple from at the first glance, the problem of time granularity becomes more and more complicated when we start to study it. Our contribution introduces graphic solutions that combine multiple aspects of the parameter time, and particularly multiple granularities. As a first step, we initially propose a visual comparison of 25 alternative calendars, covering a wide range of historic periods and cultures or civilisations. The contribution will present the concepts and ideas behind this research, as well as their practical applications on the tests cases and accordingly it possible benefits for researchers and practitioners in historic sciences