I'm sure there were times he desperately wanted to beat answers out of me, but the problem was that because I am spatial relations-challenged, I couldn't really provide them until I had figured out exactly what I required for the story to work as conceived. Was Lodi travelling west or east? If Theuderic was traveling to Amorr, why did he have to go through Malkan? The plot affected the geography and the geography affected the plot; as JartStar noted himself when he introduced the map to his Cartographer's Guild.
"The map took nearly a year to do as author didn’t know where certain locations would be until he had worked out the plot! It meant a lot of revisions all of the way until the day it was literally going to press."
The particular challenge was how to portray the allies and provinces of Amorr, since they were too small to show up on the continental map. The first attempt proved a little confusing; the editor at Marcher Lord actually got it backwards. But the zoom lines he suggested worked very well. It did lead to one minor problem in the text, as Falerum was described at two points in the original text as "the largest ally", which is quite clearly not the case. But that was cleaned up in the errata.
As for rivers and lakes, they were left off for legibility reasons. In general, it can be safely assumed that every major city is built on a river, as is the case with regards to nearly all medieval European cities. Most fantasy maps that contain rivers are entirely misleading, as they only feature one or two rivers when the number of cities shown would indicate the need for an order of magnitude more; for some reason most fantasy lands don't contain a reasonable number of lakes either. Given my ferocious hatred for long literary river journeys, it is totally appropriate that the rivers are not shown on the map as they will never, ever, feature in such a regard.
The map of Selenoth can't hold a candle to the beautiful map of Middle Earth that I once owned in the form of a much-loved jigsaw puzzle. I can't think of a single map that does. But I hope the readers find it both attractive and useful in following the story; thanks to JartStar's heroic efforts, I think it is more geographically credible than most of the maps one sees in the genre.