How are borders determined?

[vormuir]

In areas where the culture-borders of rival civilizations overlap, how does the game determine which tile is whose?

I can see that more culturally powerful cities tend to grab tiles away from weaker ones. But what exactly is the algorithm? And is it only about those particular cities, or does the cultural "weight" of the whole civilization play a role?

Also, when I put the cursor over a tile, the tile description usually includes something like "65% Chinese" or "91% Roman". What's that about? And how (if at all) does it link to who owns which tile?

Thanks in advance,

Waldo

 

[Zanmato]

I think it's down to each city itself in determining if it owns a surrounding tile or not. Of course, you may have many cities overlapping the same tile(s) so I guess the cultural value of each will come into play. As you said, a more powerful culture city will eventually win over the tiles from a weaker city but not always the city itself as that is dealt with differently (ie. units, native population). It is possible to have an enemy city completely surrounded by your own borders. The nn% info on a tile is pretty useless as a tile can only be under control by one Civ at anytime but it serves as a good indiction of how and where the culture battle is being won and lost. The algorithm for me is more culture than AI means more tiles and eventually with any luck a couple of city flips. That's really all I need to know.

 

[RickT]

The "75% Chinese" readout as you scroll over a square gives you an idea how firmly a give civilization holds that square. You can tell which way the culture battle for a given square is going by examining the same square over several turns. If the nearest Persian city is generating more culture in that square than the Chinese, the percentage number will fall toward 50%. Once it would drop below 50% (meaning the Persian city is pouring more Culture into that square than the Chinese city), the square flips. It's more complicated if there are three squares competing for the same square.

It's possible to control a square with a very low percentage if control is uncontested. I believe (but haven't checked) that the square has to go all the way to 100% before the border can expand and start growing into the next ring of squares.

I don't know the exact algorithm used. Obviously, the more culture the city generates, the faster that will happen, and I think that the culture is spread around the border of the city evenly. Cities definitely work differently--a city can be well below 50% before it revolts and eventually flips. The number of military units in the city is apparently a factor, as is whether or not your state religion is present in the city. I've gotten very different results when cities were involved, so I believe it's more of a probablility-based algorithm than absolute certainty (as the percentage in the city declines, there's an increasing chance of a revolt and later a flip). I also get the feeling that it's harder to flip subsequent cities.

 

[KrikkitTwo]

Basically each square has an amount of culture for each civ

The civ with the most culture on the square gets it IF that square is also in the proper distance from a city of that civ

The tile accumulates culture based on the culture production of nearby cities

The formula is

Culture a tile gets per turn=Culture City gets per turn*Factor

The factor is 1-5 depending on the Cultureal Level of the city - the distance of the tile (so a tile on the edge of a city's Potential borders would get 1 culture fore every culture the city produced, a Tile diectly adjacent to a Legendary city would get 5 culture for every culture the city produced)

If a tile has culture from multiple civs, then whichever civ has the most gets the tile

So if a tile has 300 Roman culture and 100 Malinese culture, then it would be Roman (If the Romans had a city in range) and display 75% Roman.

The tiles next to a newly founded city in an area where ther are no cities get a small amount of Free culture (1) so that they have
1 Roman Culture... 0 anything else, so 100% Roman (as soon as you found it), and you get them.

City flipping is a Related matter (it Also involves population of the city, Military units and State religion as well as the culture ratio of the tile)

 

[Roland Johansen]

Basically each square has an amount of culture for each civ

The civ with the most culture on the square gets it IF that square is also in the proper distance from a city of that civ

The tile accumulates culture based on the culture production of nearby cities

The formula is

Culture a tile gets per turn=Culture City gets per turn*Factor

The factor is 1-5 depending on the Cultureal Level of the city - the distance of the tile (so a tile on the edge of a city's Potential borders would get 1 culture fore every culture the city produced, a Tile diectly adjacent to a Legendary city would get 5 culture for every culture the city produced)

If a tile has culture from multiple civs, then whichever civ has the most gets the tile

So if a tile has 300 Roman culture and 100 Malinese culture, then it would be Roman (If the Romans had a city in range) and display 75% Roman.

The tiles next to a newly founded city in an area where ther are no cities get a small amount of Free culture (1) so that they have
1 Roman Culture... 0 anything else, so 100% Roman (as soon as you found it), and you get them.

City flipping is a Related matter (it Also involves population of the city, Military units and State religion as well as the culture ratio of the tile)

Interesting.

Question: would a tile at distance 3 from a city (2 horizontal tiles inbetween the city and the tile) at culture level 80% get 'culture production of city' * (4-2) per turn? And I suppose that mutiple cities can contribute culture to the same tile.

 

[cabert]

And I suppose that mutiple cities can contribute culture to the same tile.

true
if you have 3 cities pushing one square, you can ovewhelm a legendary city

 

[Roland Johansen]

Is the culture from a great artist applied according to the same formula?

 

[KrikkitTwo]

Not exactly sure about Great Artists, It could be they adjust the City's Level first and then apply the formula. (also that information is collected from what has been heard rather than tested.)

 

[Roland Johansen]

Ok, thank you for the information.