The Roman Empire would not have been possible without its roads. They connected Rome with the furthest corners of its dominion, from the Scottish border to the Arabian sands. Roads were the veins through which flowed the information, goods and soldiers that kept the empire healthy and strong.
But Romans were better road-builders than they were map-makers. No contemporary chart of the road network survives; the closest thing is the 13th-century Tabula Peutingeriana, a 1-by-22-foot copy of a now-lost, but certainly equally unwieldy original. Strangely, it takes a decidedly 20th-century cartographic motif to bring the importance of Rome's roads truly into focus.
This map is modelled after the iconic London Underground diagram first produced by Harry Beck in 1931. Borrowing from the rectilinear design of electric circuits, Beck sacrificed geographical accuracy to simplicity and legibility, evenly spacing stations on straight, colour-coded lines – and creating a design icon in the process, the oft-imitated Tube map (see also #603).
This map, designed by University of Chicago statistics major and admitted “geography and data nerd” Sasha Trubetskoy, is subject to the same Faustian/Beckian deal, surrendering accuracy for effect. But what an effect. Finally, the importance of Rome's road network is visualised.
A note on that accuracy-versus-effect thing: the map shows the road system circa 125 AD, and only includes roads that did actually exist. However:
→ At its height, the Roman road network included more than 370 great roads, covering a total distance of more than 400,000 km (250,000 mi) of roads, over 80,500 km (50,000 mi) of which were stone-paved. Only a selection of main roads, and of major cities are shown here.
→ While many roads are named and indicated as they existed (e.g. Via Appia and Via Delapidata), some roads have been merged (e.g. the Via Latina, from Rome to Capua, was subsumed into the Via Popilia, from Capua to Regium).
→ The name of some roads has been stretched to cover a greater distance (e.g. the Via Aquitania only referred to the stretch between Narbo and Burdigala, but here refers to the road all the way up to Colonia Agrippina).
→ Some roads for which no name survives have been given an invented name (e.g. Via Claudia in North Africa, after the emperor who commissioned it).
→ Ireland is not included on the map because it was not part of the Roman Empire, and thus did not contain any Roman roads.
Those caveats being understood, it is a joy to use this 'Tube map' as a guide for imaginary travels across the Roman Empire, from Rome, the caput mundi (i.e. capital of the world) itself, to Eburacum (York) for instance. You take the Via Aurelia to Luna (a former city in Etruria), thence the Via Julia Augusta to Arelate (Arles, in France), then north on the Via Flavia I, switching to the westbound Via Flavia III at Cabillonum (Chalon-sur-Saône). At that road's terminus in Gesoriacum (Boulogne-sur-Mer), you cross the Channel to Dubris (Dover), where you rush north on the Via Brittanica past Londinium for the last stretch.
Add some dice and chance cards for attack by Gaulish brigands (two stops back), roadside promotion to centurion (one stop forward) and rebelling natives (skip one turn), and you've got yourself a cool new board game!
The map does not include sailing routes, which would be the preferred way to cross the Mediterranean. In summer, Rome to Byzantium would take two months on foot, one month on horseback and about 25 days by ship. Roman Roads is a work in progress; Sasha plans to publish an updated version soon.
Check out the map (and/or order high-res prints) at this page of Sasha Trubetskoy's website, which offers many more cool maps, including a map comparing the population of Moscow to that of other Russian cities, one showing the distance of Hawaii to the nearest land mass, and one showing the conurbations spanning the U.S.-Mexican border.
For more detailed, interactive views of the Roman road network, visit Omnes Viae, a Roman routeplanner; and Orbis, the Stanford Geospatial Network Model of the Roman World.
The Ancient Paths by Graham Robb offers a fascinating (though not entirely believable) theory of the pre-Roman, Celtic road network covering Europe.
For more on roads leading to Rome, check out #754 on this blog.
Many thanks to all who sent in this map, including Theo Dirix, Leif G. Malmgren, David van der Werf and Irene Carrión Álvarez (I'm sure I'm forgetting a few).
Strange Maps #845
Got a strange map? Let me know at strangemaps@gmail.com.
Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
- There is no sound in space, but if there was, this is what it might sound like passing by Earth.
- A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
- Yes, in space no one can hear you scream, but this is still some chill stuff.
First off, let's be clear what we mean by "hear" here. (Here, here!)
Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.
All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.
BepiColombo
Image source: European Space Agency
The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.
Into and out of Earth's shadow
In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.
The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."
In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."
When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.
Magentosphere melody
The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.
BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.
MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.
Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.
