Hello! I'm wanting to play on the real world with a friend and I'm trying to figure out how to make the world's size 1:1 using the scale factor. I know the map you used was 1:10m but you also have a resizing algorithm and I know nothing about python so I don't know how that correlates. Any help on how to generate a 1:1 map would be helpful. Thank you in advance!

Tbh, it's been too long, but I'll do some calculations here (so you can double check if I did it right).

Let's say 1 pixel = 10m (which I don't think is correct, see below).

The width I resize the map to is 8064 pixels (the high-detail version).

The width of the original map is 21 600 pixels (the large version).

So that means I scaled down the map 8064 / 21 600 = 0.373333333333, so to about 37%. Or alternatively 21 600 / 8064 = 2.67857142857 about 2.68 times smaller.

So, for a 1-1 that would mean: 10 * 2.68 = 26.8 scale required.

Why I think the 1 pixel = 10m is incorrect:

1. The circumference of the earth is 40 007 863 m, there are 21 600 pixels in the map, so according to the map the earth's circumference is only 216 000 meters. Which is not correct.
2. There are two versions of the map, a low-res and high-res, with different resolutions. So they cannot both be 1 pixel = 10m.

So if we instead assume 21 600 pixels wide = 40 007 863 m (this is around the equator then I guess), and 1 cell in Factorio = 1m. Then:

That means 1 pixel = 40 007 863 / 21 600 = 1852.21587963 m

Thus, the scale we'd need would be: 1852.22 * 2.68 = 4963.9496

To be honest, I have no clue which would be correct. Probably neither. You might want to count the number of pixels of a place you know, and then search how big that is supposed to be, and then calculate a scale specifically for your starting location.

I don't recommend going beyond scale 4. I tried multiplayer with scale 6 and the closest oil generated so far away that we couldn't secure it before the biter evolution got beyond our technology.

The other thing to consider is that the earth is not flat (fun fact :), so no scale gives a 1:1 experience, except in some places depending on the scale factor and projection used.