I am trying to map the development of Ostia Antica, which was an important port city for Rome, through the Roman Era. My data collection project is going fairly well. I have chosen the locations I want to map, and have at least one photo for every location, the date it was built, what each location was, and how it changed through the centuries. The concern I have with my data relates to the dating of the buildings. Some of the locations I have very precise dates for, either a specific year or a range of two or three years, for others I have the reigns of Roman Emperors, and for others I only have centuries. Sometimes the centuries and the reigns are split into early, middle, late, or halves and quarters of centuries. So, I am going to have to find a program with a time slider showing the different time periods or perhaps multiple bars or I am going to have to find a way to standardize the data.