|Abstract||Most of the existing approaches to visualizing the vector field ensembles are achieved by visualizing the uncertainty of individual variables of different simulation runs, for example, geometry distance, statistics, variability etc. However, the comparison of the derived feature or user-defined feature (e.g. vortex) is also of vital significance since they often make more sense according to the domain knowledge. In this paper, we present a new framework to extract user-defined feature from different simulation runs. Specially, we use a bottom-up searching scheme to help extract vortex with a user-defined shape. We further compute the geometry information including the size, and the geo-spatial location of the extracted vortex, and design some link views to compare them between different runs. Results show that our method is capable of extracting user-defined feature across different runs and comparing them spatially and temporally.