It assumes some basic knowledge of overlays, as well as of the very nice size reduction guide written by Brassem. In addition it assumes some Photoshop knowledge (or a graphical program with similar features)
It runs a bit longer than I thought it would be but I hope it can be of use!
Check it out on youtube here:
http://www.youtube.com/watch?v=ptw0gvQbLFM&hd=1
Note, it is uploaded in 1080p and you should be able to see it in that! If it's not listed as an option reload it. Right now sometimes it comes up max 480p, sometimes 720 and sometimes 1080. Maybe because it was just now uploaded.
Theyre in the description but again some useful links:
Resize guide
Lat Lon conversion
Baloogan Campaign basic overlay help
Latest beta versions of GMap (allows Google maps, scroll to bottom for latest!)
Let me know if you liked it!
And in case you dont know what I mean here's an example showing from left to right: stock terrain, blending into low detail overlay, blending into high detail overlay:

