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ORBIS is an interactive scholarly work that allows readers to examine the movement of goods and people in the Roman World through the creation of a historical transportation network model and its publication using interactive maps and information visualization. It consists of a large-scale spatial database that utilizes robust pathfinding to give real-time route calculations to users, various user interfaces into that database, and a host of scholarship explaining and demonstrating its use.

A hi-res poster detailing some of the functionality of ORBIS v2

Since its release in May 2012, it's proved remarkably popular among academic audiences and the public. The original project was created under the direction of Walter Scheidel, with significant support from Stanford University Library's digital humanities and digitial library support units.

A version 2 of ORBIS was proposed and is currently under development, and will extend the functionality of ORBIS quite significantly. While the site is public while development is ongoing, its official release date is set for May 2014. Its new functionality consists of:

The expansion of the road network to include minor roads in areas where we have more detailed information available. These minor roads will be selectable as modes in the same way that rivers, coastal and overseas routes are selectable. Here we can see the minor roads in blue for the Italian peninsula and nearby islands.

Various increases in functionality are now available to the user. Some of these were only possible with direct queries to the database, while other interactive functions come from the fact that ORBIS is written entirely using D3.js, a JavaScript information visualization library that gives greater flexibility in information display and interaction.

Routes now include the ability to contrast the duration, distance and expense of the individual segments, allowing readers to see the dramatic difference between duration, distance and cost seen in the available modes of transportation in ORBIS.

Improvements to pathfinding functionality for the PostGIS database on which ORBIS runs now allows for the calculation of dynamic distance cartograms from any point, using any vehicle, mode, or time of year settings. For instance, the above cartogram from Carthago Nova. Cartograms can be run by clicking on sites or via a Cartogram tab that provides the same kind of interface as routes.

An entirely new form of visually representing the aggregated results of the ORBIS model is now available in the form of a "Minard Diagram", which takes its name from the famous Minard's Map of Napoleon's unsuccessful invasion of Russia. In ORBIS, the thickness of the lines indicate the number of distinct routes that take the same path along the network. This is created by running paths to or from every site (in the example above the model has run every path to Carthage for a particular month and set of modes) and then combining the results based on shared geographic paths. The visual effect is to show major transportation arteries into and out of particular sites in the model.

Another new feature is the ability to create territorial surfaces from the points that represent sites in ORBIS. This capacity, which was used to create the static isochronal and isophoretric maps in the initial ORBIS implementation, comes from the ability to generate a Voronoi diagram on-the-fly with D3. For ORBIS v2, this Voronoi is created based on the color of sites, which indicates which category they occupy whether that category comes from a measurement of the time or expense it took to reach them, as above with the isophoretric map from Alexandria, or if used in conjunction with the clustering feature described below.

One of the unexpected benefits of enabling the calculation of cartograms from any site in ORBIS was the ability to then cluster the remaining sites according to those calculations. The results, seen above, is a simple division of the world as represented in the model, giving users the capacity to define a "frontier" setting by which they can indicate if the cost to reach a site was not significantly more for multiple centers, then it could be designated as a fronter rather than a member of another cluster. The above map shows in light blue the regions where the cost to reach was cheapest from Rome, in dark orange cheapest from Beroia, in light orange cheapest from Alexandria, in dark green cheapest from Sarmizegethusa, and in dark blue regions where the cost to reach was nearly the same for multiple sites.

A major feature request was the ability to exclude various sites in the model to see the transportation effects for sub-regions. You can now exclude individual sites by clicking on them, or select various regions to include or exclude using the Select Sites button. The routes and cartograms will run will now reflect those excluded sites, which can sometimes cause dramatic differences. 

Another new feature is the generation of static images of each route and cartogram, along with citations for text as well as planned API citations, all of which are available in simple grid and tabular views, such as the routes and cartograms seen above. Clicking on each will redisplay the cartogram or select the route. It's planned to also include clusters and minard diagrams in this view.

Finally, not seen in screenshots is the functionality to export the map as SVG or export the results of the cartograms as a table. Also planned is the ability to export GeoJSON data for use in traditional GIS applications like ArcGIS. Along with updates to the text that explains the scholarship and technical work done to create the site, there are a few more features planned for the final ORBIS v2 launch. Until then, feel free to experience the site in its current beta form.