Factorio Forums

1: I was receiving attacks from bugs, so I checked the map by pressing M
2: There were no bug nests within 10 map blocks of my pollution cloud
3: I expected there to be red enemy markers within my pollution cloud

Additional Details: I drove around my pollution cloud and a clump of nests suddenly appeared on the minimap

The map does not show enemies in real time.

Radars reveal individual sectors of the map. When they do that, they will mark the enemy bases on the map. When you walk around, you also reveal sectors of the map, marking enemy bases. Whenever sectors of the map are not revealed, the state of enemy positions is frozen in time.

The fact that the pollution is drawn in real time might be leading you to thinking that all of the map is in real time. But it is not. One trick you can use to exploit this: Enemy bases consume pollution to create biters/spitters. When you see individual sectors of the map that have drastically lower pollution than their surrounding, or might be flickering in pollution intensity, this hints towards there being a sink for pollution. This is either trees or enemy bases. If you don't see either, it might in fact be an enemy base that you have not revealed yet. Possibly it is new and was formed by enemy expansion.

The map can also show enemies that aren't there anymore. Very noticeable with artillery. The shells reveal enemies moving towards you, but the red dots stay there when the shell moves out of range.

What the above two posters describe is called the Fog of War. Simply put, you do not have real time, fully-up-to-date information on the map. Radars have two ranges, a Visibility range that they reveal full time, and a Scanning range, which they reveal one chunk at a time but do not continuously scan. So, the information on them gets old and outdated.

HOWEVER - that is not the only potential source of your problem. Are you using mods? One mod in particular, Rampant, seems to spawn bugs on the fly. No nests anywhere near the pollution cloud, as revealed by the Visibility range of the nearby radars, yet biters attacking nonetheless. I’m not sure if the mod spawns them or triggers them from outside the pollution. Either way, this mod is another possible reason for what you are seeing.