You wrote:
But from the same URL, I read (bold italics mine):From The shape of the Roman world, Version 1.0, April 2013, Walter Scheidel, Stanford University http://orbis.stanford.edu/assets/Scheidel_59.pdf‘ORBIS: The Stanford Geospatial Network Model of the Roman World’ simulates the time and price costs of travel by land, river and sea across the mature imperial transportation network, notionally approximating conditions around 200 CE.
It is clear the prices in the edict of 301 AD are used, but only to show the difference of cost for the various modes of transportation.This goal may seem especially difficult to reach when it comes to transportation expenses. Faute
de mieux, the model relies on the price ceilings ordained by Diocletian’s Prices Edict of 301 CE, which
alone yields concurrent information regarding road, river and sea travel. We may leave aside the question
whether this text documents realistic price levels: only price ratios between different modes of transport
are of relevance to our model. All that is required is that these price ceilings are not both massively and
inconsistently wrong. Comparative evidence suggests that this modest condition is indeed met by this set
of data. With the help of ORBIS, it is now possible to determine that the envisaged price ratio for moving
a given unit of cargo over a given unit of distance is 1 (sea) to 5 (downriver)/10 (upriver) to 52 (wagon).
Jay, you also wrote:
However, from the same URL, I read (bold italics mine):From History Today http://www.historytoday.com/jasmine-pui ... cient-rome Bold italics are mine.
ORBIS is based on a simplified version of the giant network of cities, roads, rivers and sea lanes that framed movement across the Roman Empire. The Stanford team has relied on data such as historical tide and weather information, size and grade of road surfaces and an average walking distance of 30 kilometres per day. Hundreds of cities, ports and routes, vehicle speeds for ships, ox carts and horses, as well as the variable cost of transport have been logged. The data mainly focuses on the period around AD 200, when Septimius Severus expanded control of Africa and Roman power was at one of its peaks.
Cordially, BernardThe project also revealed just how little evidence we have about Roman transport speed, costs of sea vessels and speeds of river boats. Data was also limited on price fluctuations, the only reference coming from Emperor Diocletian’s edict of 301, which was intended to curb inflation.