Factorio 0.16.x/0.17.x/0.18.x note: RSO doesn't work with map preview - there will be no ores there with RSO active
Factorio 0.17.x/0.18.x note: Be aware that Railword preset increases size of resources significantly - if you use it RSO will have much bigger fields. Stay with Default preset when using RSO.
This mod overrides in-game Perlin noise based resource/units spawning system by region divided spawning system.
It changes resource spawning to be region based - by default regions are big which promotes using of trains. Resources will be more sparse so more logistics will be required to supply your base. As a bonus resources further away from start location will be more rich.
Important - frequency of resources works differently with RSO active. Frequency set in map settings menu will make resource more or less frequent in comparison to other resources. Enemy base frequency works normally (there will be more or less bases based on setting).
RSO also controls spawning of biter bases to make it easier for a player to move further into the wilds, but don't expect resources to be biter-free.
Mods that don't modify resources should work without problems. Support is present for most of large mods (Bob's mods, Yuoki industries, Uranium power) and some of smaller ones.
If you receive information about not supported ores (will be printed after game start) please post in discussions tab and I'll try to add support for them (please write which mod adds the ores if possible).