I stick to a few
"guidelines" when generating worlds myself to ensure that I always get a healthy amount of goblins, elves and humans as neighbors
(I don't use legends viewer, though I probably should). So I treat these as
"indicators" of a healthy civilization, though its probably easier to just check from legends viewer and extrapolate the data from there. A combination of both techniques is probably the most reliable as sifting through legends for population numbers is particularly cumbersome and unreliable.
These pertain more for world gen instead of legends. But they are still applicable as they use the same site symbols.
- Pay attention to the world map after stopping world gen and before exiting the world gen page. You want to highlight the various symbols of sites and check whether they are occupied by the races you want. What you want is
elven forest retreat instead of just
forest retreat, and stuff like that. The "elven" shows that the site is occupied though it does not tell the population. Sometimes, sites get conquered so a dwarf fortress shows up as "the goblin fortress of so and so" even though the site symbol shows a dwarf fortress. Conquered sites that are abandoned show up as ruins instead. It helps if you're familiar with the symbols so you can tell at a glance instead of highlighting them manually, that way you can just abort world gen instead of saving the map and checking legends mode, it saves you some time. I find the
map legend on the wiki very useful in that regard.
- You can also tell at a glance from the world gen map whether the goblin sites are in range or not, its 30 tiles for goblins and 10 tiles for towers. Also, tight clusters of sites that are not empty might indicate a strong population presence.
- Make sure those races are still reproducing babies, I tab down to the bottom of the units list in legends mode to check. Not a big requirement for goblins since they can steal babies but its probably better if they are also producing more of their own kind.
- If you've got time to burn and want to really to be precise about it, you can look at the world gen map while the years count down and stop every now and then to check the sites. I've gotten to the stage where I'm familiar with the map symbols so I can tell when the sites are all abandoned
(the map symbols change to reflect this) then I'll stop world gen before it even reaches the end year and roll up a new map.
- There are other things you can do to boost population numbers for races even before world gen. For example, mountains are necessary for mountainhomes and hills are necessary for dwarven hillocks. Boosting those numbers will increase the number of sites available for dwarves to occupy during world gen. Likewise, increasing evil biomes in the world can boost the number of sites goblins can occupy, the same thing goes for elves with forests and humans with grasslands and plains.
- The default regions and islands when you design a new world with advanced parameters are usually quite balanced but you can tweak them to your liking to boost population. Likewise, increasing the number of civilizations can increase the spread of that race across the map instead of all of them being concentrated in one particular region of the map. It also acts as a buffer for megabeast attacks that wreck entire civilizations during first few years of worldgen before they can establish sites and defend themselves.