Submitted by Xsanda, who says:

Over the Christmas break I was inspired by your E-Road Network Map, and wanted to create my own map. I chose the Asian Highway Network, a similar system to the E-Road network, as there seemed to be very few maps of the whole network, and the only ones I could find were either too high-level or too vast to easily read. This is my take on the network.

However, one thing I was not sure how to represent on the map was international borders, which I think would be more important in Asia than Europe, as without Schengen any route-planning would have to involve considering visas for travelling between countries. There is also the problem that some borders are completely closed, such as the North Korea | South Korea border on AH1 and AH6: how would you suggest that I show this?

Another issue I had while developing the map was fitting 45° angles into the grid system. I rounded these distances to the nearest ¹⁄₈ of the line width, but this did mean that it became harder and harder to stick to the major divisions of the grid as I developed the map further, and any diagonal distances are slightly different to the horizontal/vertical distances. Do you have any advice about this?

Transit Maps says:

Wow – you’ve certainly nailed the look and feel of my E-Road map, Xsanda! As a result, this makes a great companion piece to my previous work. I find it especially interesting that the two systems overlap somewhat to the west: Turkey, Russia and the Caucasas region would seem to have many roads that would be designated as both an E-Road and an Asian Highway, though signage as both would probably be pretty intermittent. 

Also of interest is the numbering system: unlike E-Roads and US Interstates (which arrange numbers into a continent-spanning grid), the Asian Highway network uses numbers 1-9 to represent cross-continent routes, with two- and three-digit numbers grouped by region, as Xsanda explains:

Numbers 10-29 represent Southeast Asia, with 10-19 on the mainland, and 20-29 on the islands of Indonesia and the Philippines. Numbers 30-39 are located in Northeast Asia, and 40-59 are in South Asia, the Indian subcontinent. Numbers 60-69 are in Central Asia, 70-79 are in Iran and Afghanistan, and 80-89 are in Turkey and the Caucasus region.

Design-wise, international borders do present an interesting challenge, and I’m not afraid to admit that I intentionally left them off my map simply because it seemed like too much hard work. I also liked the idea of presenting a Europe unified by this network of highways, even though the Schengen Zone is much smaller than the total area of the map. You can take the plunge and add them, but be aware that the distortion of the landforms to fit the stylised look of the map will carry across to borders, which could result in some very odd-looking countries!

Regarding closed borders, they could be pretty easily indicated with an appropriate icon that’s explained in the legend – this could be a solid black bar or “X” across the highway at that point, or some other appropriate yet graphically simple symbol.

As for the grid, I wouldn’t worry too much about breaking it. On a map like this, it should really act as a guideline only: the more important thing is to make a map that feels balanced, and I think you’ve done a pretty good job! Now, what other continent-spanning highway networks need mapping?