Radar

Radar is an electrical entity that reveals terrain and keeps an area around it updated on the map. It provides both local visibility and long-range survey scanning, making it useful for base expansion, exploration, and keeping distant regions charted without direct player presence.

A radar continuously charts a nearby area of 7×7 chunks, or 224×224 tiles, centered on the chunk it occupies. This nearby scan is updated by a pulse roughly once per second at full power, and it keeps that area brightly visible on the map. If the radar receives less power, the pulse takes longer and the nearby map can begin to blink, especially in solar-powered setups around dawn and dusk. At 20% power, the radar pulses about once every 4 seconds, which is still enough to keep the area continuously lit on the map, though with reduced detail. A single solar panel can provide 20% power, or one isolating accumulator can be used for every five radars.

Beyond its local coverage, a radar also performs long-range survey scanning. It scans one distant chunk each time its sector scanning progress bar fills, which takes 33.333 seconds at full power. The bar can be seen by hovering over or opening the radar’s details. Long-range scans appear on the map as a single chunk lighting up for several seconds before slowly fading. The radar scans unexplored chunks first, and it also generates chunks if they were not generated at the time of the scan. This long-range process covers a 29×29 chunk area around the radar, excluding the nearby 7×7 chunk area, for a total of 792 chunks per full cycle. If everything in range is already explored, the radar keeps rescanning the chunk that was scanned the longest time ago. Multiple radars share the same long-range scanning space and avoid scanning chunks that are already being scanned by other radars.

Radar coverage also improves map interaction. The area it reveals is shown brighter than the rest of the map, allowing the player to zoom from the map into the normal world view and making blueprint placement and deconstruction planning possible. A roboport provides similar charting for a 5×5 area, but radar has the larger range and the survey function.

Each radar is connected by circuit network to every other radar on the same surface. Any circuit signal sent into one radar is output from all other radars on that surface. If a radar loses power, it loses this circuit connection. Since the radar has no GUI of its own, the output is observed through connected objects such as electric poles.

Radar data is tied to charting, which is the process that copies scanned chunk images into a force’s map. A scanned chunk stays actively charted for 10 seconds, after which it becomes fog of war again unless it is re-scanned. If the contents of a chunk change between ticks, those changes are also charted into the map; this can affect performance if many chunks are changing at once. Even in fog of war, vehicles keep their last charted position, though trains do not. It is also possible for new alien nests to appear in a chunk after it has been scanned, so a previously clear map area is not guaranteed to remain free of enemies.

Radar also affects remote control behavior: tanks and spidertrons cannot be entered when out of radar range, but they can still be controlled and exited.