IS was consistent in the publication of produced propaganda videos and usually provided accurate location information. They tended to show obvious landmarks and distinctive buildings and sites.
For example, the video here was filmed in front of Mosul Grand Mosque.
However, battlefield footage or longer video packages were harder to verify, or sometimes contained multiple locations, or footage from third parties.
In terms of describing locations, IS did not use terms like “city” or “province.” They tended to use the term “wilayat” (ولاية), which means a state, and their territory was subdivided into multiple wilayats.
For example:
IS content primarily used the Islamic calendar. All of the content shared by the IS media arms, such as Wilayat Bayda, Wilayat Raqqa, Wilayat al-Khair, Al-Furat Media Foundation, al-Naba and Furqan Agency, used Islamic dates.
See examples here:
However, the IS-linked Amaq Agency tended to use the Gregorian calendar more than the Islamic one.
For example:
These are some websites that offer a simple method for transforming Gregorian calendar dates to Islamic calendar dates and vice versa.