Research Links

There are several websites offering, in some cases, truly outstanding historical geodata that deserve recommendation here:

David Rumsey Map Collection – an exceptional collection of historical maps curated by the unmatched legend David Rumsey.
OldMapsOnline – an excellent gateway to historical maps from archives around the world.
National Collection of Aerial Photography (NCAP) – an archive containing excellent aerial imagery, including remarkable photographs of northern Germany from the Second World War period. The archive currently appears to be undergoing restructuring, so not all normally available datasets may be accessible at the moment.
Vici.org – an exemplary historical map wiki, particularly useful for locating Roman sites.
ESRI World Imagery Wayback high-quality aerial imagery for the entire world, covering the period from 2014 to the present.
ArchaeoPro – a very informative resource explaining key aspects of aerial archaeology.
Itiner-e – a research project dedicated to Roman roads and ancient routes.
Online Coins of the Roman Empire (OCRE) – an open-access scholarly database for Roman imperial coinage.
Coinage of the Roman Republic Online (CRRO) – a major online reference for Roman Republican coinage.
Roman Republican Die Project (RRDP) – a digital research project focused on Roman Republican coin dies and die studies.
Coin Hoards of the Roman Empire