A logical acquisition captures what is accessible to the user. In simple terms, it often ignores the underlying and system files. Deleted data may be reported during a logical acquisition simply because the files are marked as deleted but they exist in the free space of the SQLite databases saved on that device. We will discuss recovering SQLite data and deleted artifacts in Chapter 6, iOS Data Analysis and Recovery.
A logical acquisition is the simplest to ascertain if the device is unlocked, as it simply captures the active user data on the device. Most tools and methods that support logical acquisition of iOS devices will fail if the device is locked. Some think that if a physical image is captured, there is little to no need for a logical acquisition. However, not all data is parsed in a physical image, which is why having access to logical image, resulting in readable data will assist in digging deep in the physical image for artifacts to support your forensic investigation...