All Roman forts and camps across the empire followed the same basic layout for hundreds of years with minor alterations according to the composition of the unit stationed there.
The fort was intended to inspire and keep soldiers safe. Very often civilian buildings and other enclosures were built nearby. Roman camps were frequently made in the vicinity of a fort. Two further layouts are below and detailed layouts of forts can be found at Castleshaw Roman Fort and Fortlet and A Short Guide to buildings within the Fort for Segedunum,
Forts were always placed near water and usually in the bend so that the river gave an additional level of protection. Horses need access to a regular and plentiful water supply and barges transport goods upstream sometimes pulled by a horse. The Romans, Rivers and Valleys page shows the placement of forts all over Scotland on how each fort and camp is on a river.