Abstract: Objectivity is a concept from continuum mechanics, demanding invariance of a measure under continuous changes of the reference frame (coordinate system). A measure should be independent of the observer, different observers moving in different frames should come to the same conclusion about an objective measure. While objectivity appears a rather natural condition for a useful measure, it creates problems for the analysis of flows because velocity fields are not objective. This has triggered quite some research in recent years in both computational fluid dynamics and flow visualization to come up with objective flow measures and resulting objective flow visualization techniques. With give an overview about existing objective flow measures. In particular we focus on generic measures, i.e., approaches to transform any flow measure into an objective one. We describe recent approaches to objectivize general flow measures and resolve a dispute about the objectivity and other desired properties of our approaches.