Its been in my todo list to convert my current Greyhawk map to use GIS (https://en.wikipedia.org/wiki/Geographic_information_system) instead of Adobe Illustrator. Now after several years of getting up to speed on using QGIS and other GIS tools, I'm happy to report that the milestone is reached, all of the terrain is geo-referenced!
This means that I have placed Flanaess and Hepmonaland on my model of Oerth, with reasonable precision needs to be added. The current map is only accurate to about a mile, so that is the current data accuracy I'm working with. This is more than enough to create maps covering the whole of the Flanaess Hepmonaland down to maps of individual countries. The beauty of GIS is that now I can do the map in various scales and sizes with proper grids as needed.
Properly projected maps are another big plus, and here is the Flanaess seen from the city of Greyhawk using and "Oerthographic Projection", which means map looks look it is seen from space. This is my preferred type of projection for fantasy maps, it has very good area accuracy and gives you an great understanding of the size and proportion of things even over large areas. The main reason against the use of orthographic projections are the fact that they are ill suited for navigational calculations for real world sea- and air-farers. But fantasy adventurers rarely needs to calculate bearing to true north, magnetic deviation and similar tasks using maps. We want to know how long the road is between two towns, how large a square mile is, and what the land looks like. These are all things that an ortho based map can tell you.
Polar maps are well suited for ortho based maps, with the wealth of geography of Oerth that are situated above the northern polar circle.
To get a realistic view of how things are related across oceans as well as landmasses even closer to polar regions are a requirement for Oerth's northern geography.
For map covering the whole world of Greyhawk there might be best to use one of the many global projections, like ESRI: 54078 Natural Earth II.
This is is only the first step in my effort to create a good set of reference maps for the World of Greyhawk using modern day tools, but even at this stage things are really interesting and shows great promise.
Thank you so much for making it possible to making this project coming true!