So I'm like 30 hours into my map.
I have revealed an area of around 4x4 the advanced radar range
Found multiple fields of everything, but no immersite at all

When I start a game in sandbox mode and just scan the map, there is much more immersite (and one always near to starting area)
Probably a bug?

If I want to spawn an immersite source, what would be the console command for it?

here is link to map:
https://pasteboard.co/J6HkHz1.png

here list of the mods i have installed:
https://pasteboard.co/J6HlUcS.png

It's quite rare, I would suggest scouting a bit more before manually trying to spawn something. I'm also playing with RSO and have only found two Imersite deposits so far on my map: https://i.imgur.com/jnroONF.png

I'm still looking for Uranium myself, but I trust it's out there somewhere

yeah I just found one, a 10 M patch, super far away from my starting position.
so it just seems to be super rare.

still strange, when I start a map in sandbox mode... it seems to be much more frequently.

on the other side, i have lots of uranium and rare metals

If you really have to spawn it in, this works fine with infinite resources but not much else as it only spawns 350 to a resource area. Changing the density only ads more resource nodes.

/c local surface=game.player.surface
local ore=nil
local size=1
local density=1
for y=-size, size do
for x=-size, size do
a=(size+1-math.abs(x))10
b=(size+1-math.abs(y))10
if a<b then
ore=math.random(adensity-a(density-8), adensity+a(density-8))
end
if b<a then
ore=math.random(bdensity-b(density-8), bdensity+b(density-8))
end
if surface.get_tile(game.player.position.x+x, game.player.position.y+y).collides_with("ground-tile") then
surface.create_entity({name="imersite", amount=ore, position={game.player.position.x+x, game.player.position.y+y}})
end
end
end