Systems and methods for determining spatially dense dynamic properties of a structure are disclosed. In particular, spatially dense mode shapes are determined using acceleration records collected when one or several sensors are moving. The mobile sensor gathers vibration response data for the structure as the mobile sensor moves over the structure. The vibration response data is used to extract a fine grid of modal coordinates with a reduced number of sensors and without requiring mode shape expansion. The high spatially dense mode shapes can be included as part of accurate numerical models for the structure that can be used for a variety of purposes, such as damage detection, earthquake engineering, wind engineering, and other suitable purposes.