As a map maker, i see there are 2 main reasons why there are not many large 1:1 maps in Il-2:
- It's very time consuming, hard work to make. Think about a area full of rivers and lakes, and consider that you have to work in a raster tga image with 1px = 50m to draw, pixel to pixel, every river or another water body. Sea and some lakes are easy to make, as you can select the area directly in SRTM or Landsat/photo images and use bucket fill tool, but rivers are a pain in the butt task, as you have to recognize manually where the thalweg is in drainage basins, and draw pixel to pixel the river's way. Make roads and rail is the same thing, except that you work in a smaller image where 1 px = 200 m.
- It's very resource demanding. Map_c, the image file used by game engine to know where in the map is soil or water, is a 50m/pixel as I stated above. So think about a 1000 x 1000 km map: you have a 20k x 20k pixels map_c raster tga image. Other files, except ed_map0x, are 200 m/px tgas, so you have a 5k x 5k pixels images. You have to make some image processing tasks like color or wizard selecting, bucket fills, blur and so on in these huge image files. So, you need a powerful computer with a plenty of RAM, HDD storage and processing power, and a lots of patience with computer crashes and freezes for this.
Another problem is game engine limitations, as in Il-2 you can't have maps bigger than 1000 x 1000 km. In theory, you can render this kind of map ingame, but FMB cannot write waypoints with more than 6 digits coordinates, so only the SW portion of map up to 1000k,1000k coordinates will be usable for missions.
