Global Explorer, you are definately on the right track with this 'zone-ing' of intelligence. The dots and markers provided by SH3Gen on the tracking-room map gave a false sense of accuracy. Too pin-pointy. When I look at the map belonging to my savegames I keep getting the desire to flank to the nearest dots. Only to find out it was 'a mistakeh toh makeh'.
Providing general areas, yet not too big, is the way to go (imho).
Looking at the SH4 screenshots I find the areas showing merchant and naval activity in large scale overview somewhat obvious. Looking at the occupied ports and airbases it's not so difficult to judge this in one's mind. If you could find a way to show more traffic lanes between ports that would be great. I was thinking of showing the waypoint routes with (wide) rectangles instead of lines as in the editor. And then 'adding' or logic 'OR-ing' those colored areas together as you did with the airbase coverage. That should create plenty of overlap. And perhaps colorcoding/shading those areas (or parts thereof) based on average spawning frequency to show hot areas. But I do not know what tatukGIS allows you to do in this regard.
Lastly, I would like to beg you to make a SH3 release once you are finished with this trend. Please don't limit yourself (and us) to SH4. SH3 is still vibrant enough. I really would like to sink those japs aswell (somewhat of a personal reason) but SH4 is too heavy for my PC.
[minor edit: logic OR, ... not AND. Was way past bedtime.]