You can't paint good/evil because it's assigned by DF internally during world gen.
I know this, but it still has bothered me a bit
Variance shouldn't have any effect on a fully defined PSV world. However, if you specify only some of the parameters and let DF generate the others it will do so (and I generally use fully defined PSV world, so I don't know much about how the hybrid approach works).
It seems i was incorrect here, the symbol changes for savanna/grassland, but it creates one big region with different symbols. It also seems regions depend on temperature somehow though and I left temperature to be randomly generated, which may also have been an effect, I guess in the future I should just set it to what I want everywhere.
The wiki should be able to tell you which biomes belong to the same region type. "Hills" and "Grassland" have the same biomes (savanna, etc.), while all the other biomes are present in a single region type only.
If I understand you correctly you are saying that hilly savanna and hilly grassland become the same region and savanna and grassland become the same region but it is not
my own testing tells me that broadleaf forest and conifer forest also become same region, as well as marsh and swamp becoming same region, so wiki isn't totally accurate but not especially difficult to figure it out (at least without rivers causing problems)
test world here:
[WORLD_GEN]
[TITLE:NEW]
[DIM:17:17]
[EMBARK_POINTS:1504]
[END_YEAR:1050]
[BEAST_END_YEAR:30:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:1:400:3200:3200]
[RAINFALL:0:100:3200:3200]
[TEMPERATURE:30:30:0:0]
[DRAINAGE:0:100:3200:3200]
[VOLCANISM:0:100:26:26]
[SAVAGERY:0:100:26:26]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[POLE:NONE]
[MINERAL_SCARCITY:2500]
[MEGABEAST_CAP:1]
[SEMIMEGABEAST_CAP:2]
[TITAN_NUMBER:1]
[TITAN_ATTACK_TRIGGER:80:0:100000]
[DEMON_NUMBER:20]
[NIGHT_TROLL_NUMBER:10]
[BOGEYMAN_NUMBER:10]
[VAMPIRE_NUMBER:10]
[WEREBEAST_NUMBER:10]
[SECRET_NUMBER:20]
[REGIONAL_INTERACTION_NUMBER:20]
[DISTURBANCE_INTERACTION_NUMBER:20]
[EVIL_CLOUD_NUMBER:10]
[EVIL_RAIN_NUMBER:10]
[GENERATE_DIVINE_MATERIALS:1]
[GOOD_SQ_COUNTS:0:0:0]
[EVIL_SQ_COUNTS:0:289:0]
[PEAK_NUMBER_MIN:0]
[PARTIAL_OCEAN_EDGE_MIN:0]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:3]
[REGION_COUNTS:SWAMP:0:0:0]
[REGION_COUNTS:DESERT:0:0:0]
[REGION_COUNTS:FOREST:0:0:0]
[REGION_COUNTS:MOUNTAINS:0:0:0]
[REGION_COUNTS:OCEAN:0:0:0]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:0:0:0]
[REGION_COUNTS:HILLS:0:0:0]
[EROSION_CYCLE_COUNT:250]
[RIVER_MINS:0:0]
[PERIODICALLY_ERODE_EXTREMES:0]
[OROGRAPHIC_PRECIPITATION:0]
[SUBREGION_MAX:500]
[CAVERN_LAYER_COUNT:3]
[CAVERN_LAYER_OPENNESS_MIN:0]
[CAVERN_LAYER_OPENNESS_MAX:100]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:100]
[CAVERN_LAYER_WATER_MIN:0]
[CAVERN_LAYER_WATER_MAX:100]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:15]
[LEVELS_ABOVE_LAYER_1:5]
[LEVELS_ABOVE_LAYER_2:1]
[LEVELS_ABOVE_LAYER_3:1]
[LEVELS_ABOVE_LAYER_4:1]
[LEVELS_ABOVE_LAYER_5:2]
[LEVELS_AT_BOTTOM:1]
[CAVE_MIN_SIZE:5]
[CAVE_MAX_SIZE:25]
[MOUNTAIN_CAVE_MIN:0]
[NON_MOUNTAIN_CAVE_MIN:0]
[ALL_CAVES_VISIBLE:0]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:5]
[TOTAL_CIV_POPULATION:15000]
[SITE_CAP:18]
[PLAYABLE_CIVILIZATION_REQUIRED:0]
[ELEVATION_RANGES:0:0:0]
[RAIN_RANGES:0:0:0]
[DRAINAGE_RANGES:0:0:0]
[SAVAGERY_RANGES:0:0:0]
[VOLCANISM_RANGES:0:0:0]
[PS_EL:1:1:1:1:1:1:1:1:1:1:1:200:200:200:200:200:200]
[PS_EL:1:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200]
[PS_EL:1:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200]
[PS_EL:1:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200]
[PS_EL:200:200:200:200:200:200:1:200:200:200:200:200:200:200:200:200:200]
[PS_EL:200:200:200:200:200:200:1:200:200:200:200:200:200:200:200:200:200]
[PS_EL:200:200:200:200:200:200:1:200:200:200:200:200:200:200:200:200:200]
[PS_EL:200:200:200:200:200:200:1:200:200:200:200:200:200:200:200:200:200]
[PS_EL:200:200:200:200:200:200:1:1:1:1:1:1:1:1:1:1:1]
[PS_EL:200:200:200:200:200:200:1:200:200:200:200:200:200:200:200:200:200]
[PS_EL:1:1:1:1:1:1:1:200:200:200:200:200:200:200:200:200:200]
[PS_EL:200:200:200:200:200:200:1:200:200:200:200:200:200:200:200:200:200]
[PS_EL:200:200:200:200:200:200:1:1:1:1:400:400:400:120:400:400:400]
[PS_EL:200:200:200:200:200:200:1:1:1:1:400:400:400:120:400:400:400]
[PS_EL:200:200:200:200:200:200:1:1:1:1:400:400:400:120:400:400:400]
[PS_EL:200:200:200:200:200:200:1:1:1:1:400:400:400:120:400:400:400]
[PS_EL:200:200:200:200:200:200:1:1:1:1:400:400:400:120:400:400:400]
[PS_RF:15:15:15:15:15:15:15:15:15:15:15:15:15:15:15:10:15]
[PS_RF:15:100:100:100:100:100:50:50:50:50:50:15:15:15:15:15:15]
[PS_RF:15:100:100:100:100:100:50:50:50:50:50:15:15:15:15:15:15]
[PS_RF:15:100:100:100:100:100:50:50:50:50:50:15:25:25:25:25:25]
[PS_RF:25:25:25:25:25:25:15:25:25:25:25:25:25:25:25:25:25]
[PS_RF:25:25:25:25:25:25:15:100:100:100:100:100:70:70:70:70:70]
[PS_RF:25:25:25:25:25:25:15:100:100:100:100:100:70:70:70:70:70]
[PS_RF:25:25:25:25:25:25:15:100:100:100:100:100:70:70:70:70:70]
[PS_RF:25:25:25:25:25:25:15:15:15:15:15:15:15:15:15:15:15]
[PS_RF:25:25:25:25:25:25:15:70:70:70:70:70:100:100:100:100:100]
[PS_RF:15:15:15:15:15:15:15:70:70:70:70:70:100:100:100:100:100]
[PS_RF:15:15:15:15:15:15:15:70:70:70:70:70:100:100:100:100:100]
[PS_RF:15:15:15:15:15:15:15:15:15:15:50:50:50:0:50:50:50]
[PS_RF:15:15:15:15:15:15:15:15:15:15:50:50:50:0:50:50:50]
[PS_RF:15:15:15:15:15:10:15:15:15:15:50:50:50:0:50:50:50]
[PS_RF:15:15:15:15:15:10:15:15:15:15:50:50:50:0:50:50:50]
[PS_RF:15:15:15:15:15:15:15:15:15:15:50:50:50:0:50:50:50]
[PS_DR:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:49:0]
[PS_DR:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_DR:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_DR:100:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_DR:0:0:0:0:0:0:100:0:0:0:0:0:0:0:0:0:0]
[PS_DR:0:0:0:0:0:0:100:0:0:0:0:0:100:100:100:100:100]
[PS_DR:0:0:0:0:0:0:100:0:0:0:0:0:100:100:100:100:100]
[PS_DR:100:100:100:100:100:100:100:0:0:0:0:0:100:100:100:100:100]
[PS_DR:100:100:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0]
[PS_DR:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100]
[PS_DR:0:0:0:0:0:0:0:100:100:100:100:100:100:100:100:100:100]
[PS_DR:100:100:100:100:100:100:0:100:100:100:100:100:100:100:100:100:100]
[PS_DR:100:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0:0]
[PS_DR:100:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0:0]
[PS_DR:0:0:0:0:0:49:0:0:0:0:0:0:0:0:0:0:0]
[PS_DR:0:0:0:0:0:49:0:0:0:0:0:0:0:0:0:0:0]
[PS_DR:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:100:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:100:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:100:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:100:50:50:50]
[PS_VL:50:50:50:50:50:50:50:50:50:50:50:50:50:100:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
[PS_SV:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50:50]
Maybe I should do some more testing and put results to the wiki, since right now it has no information about regions and some more testing on this wouldn't be that much work.
A volcano is a "feature" that exists within a tile, and so isn't tied to any particular region type, even if the cone may rise to mountain elevations.
in the lower right corner of the previous test I have two 3x5 blocks of mountains separated by a 1 wide strip of deserts with 100 volcanism; I have it so only medium regions will go evil and those mountains go evil, while if I change the volcanism to 0 they don't.
Rivers shouldn't split regions, as they appear "on top" (they're "features"). I suspect the cases you've seen are grassland/hill regions (they differ only by Drainage).
After some more testing, I seem to be incorrect here as well, that must have been temperature effects then, or possibly flooding, not sure.
Never seen any flooding (although someone recently said that happened, although it wasn't verified as far as I've seen). Lake formation happens during world gen and can't be controlled by PSVs, though. Elevation below 100 results in ocean tiles (which can result in very small oceans...), not lakes.
I suspect the flooding and lakes are the same things, but they seem to be somewhat controllable by elevation modification for example, or for example by rivers; here is what my worldpainter screen looks like:
(
https://ibb.co/S5hf4BW incase img tag doesn't work)
If I generate this world with 800 rivers, I sometimes get some small lakes:
(
https://ibb.co/hsm8DHH incase img tag doesn't work)
But if I generate with 0 rivers I get a huge lake:
(
https://ibb.co/Zg0WpPR incase img tag doesn't work)
I'm not sure but it also seems to be based on relative elevation, with a similar setup but larger map I was having problems with huge portions of the map becoming lakes, but by putting down a few sea tiles it seemed to prevent the lakes from showing up. I think reducing the sizes of the peaks helped as well, though I don't remember for sure and the reason I did that was because it made it must more likely for rivers to be near the volcano mountains.
You probably don't want to play a truly dead civ, as those a badly bugged: No travel possible, so no raiding. Your civ won't found sites (naturally), but you can't conquer any either, so you're relying on sites to spontaneously tie themselves to you for those nobles. If you lose your expedition leader it won't be replaced, which locks out a lot of functionality if that happens, but I think getting a mayor will get past that problem (there should be a new one elected the next summer).
not all those are problems for me, but also didn't realize so many bugs, and not a huge deal though, dying civilization is fine