Here's my simple, intuitive approach to limiting city spam: Tada

I'm strongly in favour of any food-based solution, be it mine, Demiansky's, or someone else's.  It's the only solution that feels natural.  The governor thing just seems a little too forced.  The game mechanics themselves (in this case food availability and consumption) should dictate how a typical game unfolds, not artificial rules and limits.

@outlaw : When you "spam" cities, you have the choice to put your gold in another project. My ideas come from the fact that if it's more interesting to expand already existing cities, then you won't spam.

Imagine you have 4 cities. Why would you build a 5th city if expanding one of your already existing cities get you better results ? That's what I tried to show : we build cities to get more roads, to get more population, to get more research, to get more units to build. My ideas try to give better result with less but bigger cities.

Or another idea : You have a higher chance to get bad events each turn if you have more cities. It would be based on the rough number of cities you have. 4 cities ? 4% to get bad event. 100 cities ? You are sure to get something nasty each turn.

Then you would be discouraged to spam without thinking.

But. What about conquered cities ? We need a mechanism that would allow to "merge" cities. That's what we do in the real world. City, region, country. Each of those levels has some way to enhance the life of citizens. You have 5 towns close to each other ? Create a region (that would only be considered as one town for the "bad event" percentage) but you lose a bit of control over it. You just ask what you want, and the governor will decide what to do. And if your political party lose the majority, then the governor will decide what their citizens need the most. You still can build units, but you can only "ask" for some buildings.

Another idea : Elemental has a dynasty system. Why not a dynasty system for cities ? First, strating a city should cost high, in essence in gold in whatever you want. But really costy. then after a city has reach the level 2, it can build an outpost in his vicinity. That new town can't get a higher level than the "parent" town.

Another thing I forgot : players often, very often spam cities .. to control land. Not only improvements, but land. If you have a bigger country and you deny the access to another country you get a huge advantage. More territory is never a bad thing.

How to avoid that greedy attitude ? Give other, cheaper than a new city, ways to grab land.

About units : often you create a new town to get a new place to build units. If you have 2 towns and your opponents have 10 towns, then you will be outnumbered really quickly. Because, you will be be short on population for your units before your enemies. More cities = more versatile. Maybe adding the possibility to build two units at the same time in a city would prevent this.

A good suggestion.  I've never liked the Civ mechanic of your borders being defined by your city radii (the later switch to culture was a little better, but annoying in other ways).  Speaking as a Canadian, we didn't claim the vast north by spamming cities all over the place up there!

I'm strongly in favour of a food-based solution too and I think Demiansky is on the right path, though I can see a lot more options open up. But more on that later.

Right now the reviving of the land is actually promoting city spam instead of curbing it. The reason is that cities spread the reviving, so more cities means more land means more cities means more land, etc.  

My solution:

1. Cities do not heal the land.

2. Instead the player selects a tile and imbues the land, and after that it radiates from that tile. (Optional: Maybe the spread rate decreases with range.)

3. Make the healing slightly random to prevent boring "heal circles": make the edge of healed land and wasteland more natural.

4. Maybe increase or decrease the spreading rate to accomodate this change, this needs some testing.

With this (rather small change) players who own a lot of cities don't get any benefit, quite to the contrary; cityspammers will need to spend a lot of essence to open up enough room for their cities to grow, while the essence hoarding opponent will be able to compete with the larger empire of the cityspamming player with more/better heroes/Sovereign. Hopefully this will fix the ageold TBS problem of the winner keeps on winning.

Although to really curb cityspam imho a food-based solution is needed as well this change will atleast prevent these unintended consequenses.

Food won't prevent someone to build 5 cities of 100 population instead of 2 cities of 250 population. 500 population still need the same amount of food in the game (it's linear). So spamming won't be avoided. Getting 5 cities instead of 2 will let you have : more gold, more resources, more units built per turn (5 instead of 2), faster population growth (thus more gold and research).

We did claim the west that way. That's the reason the railroad was built out west, actually. The goal was to get Canadian settlers out there and occupy the land before Americans moving west came up and claimed more of it (that had already happened around Fort Vancouver, which wound up becoming part of the US).

I mean they weren't cities, but we were building settlements out there. Outposts, if you will.

I am nervous about a food based solution.  It can be very hard to tweak the numbers just right, and it is hard to prevent having lots of smaller cities rather than a few big cities.

However, something similar could be done at a more abstract level.  For example, the underlying game fiction strongly supports the idea of few cities.  Most of the land is blasted and lifeless.  You may put a military outpost in such territory, but no one is going to voluntarily live there if they can choose something better.  Perhaps, food aside, territory can only support so many people.  That could be implemented as needing a minimum number of surrounding empty squares to support a given level of population.  So if you want a big city, you'll need to leave lots of room.  And if other people are putting down outposts near you to compete for resources, you'll want to wipe them out rather than conquer them. 

So, you could say that a first level city requires a minimum of twenty squares not claimed by some other population center or kingdom.  A second level city could require fifty, a third level city 90, etcetera. 

This idea would also play into the resource gathering that Boogieback was proposing.  That whole area is within the city's "influence," and you can harvest resources within that area.  However, those resources may not be within the city's actual defenses.  For example, mines and orchards and the like are typically outside of city walls.  A small number of people will live adjacent to them, but they exist at some distance and a foreign military can occupy them and deny their use to the city.

One could also require that a road be built connecting the resource to the city, at which point it could be harvested remotely so long as it was in the city's sphere of influence.

Another way to think about this is to make the kingdom boundaries really mean something.  The kingdom boundaries are the sum of the city boundaries, which themselves represent the area which the city's residents have influence over - exploring, mining, harvesting, etcetera.  Major constructions are represented as actual tile builds, but the remaining squares of influence represent territory that the city uses in less intense ways (such as perhaps just siphoning off the remaining energy to bolster the fertility of the rest of the city).  If you don't have enough free space, the city's growth will be capped.

Using this approach, spamming in your central area will be an extremely bad idea, as you will cap your earliest cities' max size.  You may want to put outposts in enemy territory and try to limit the size of their cities, but eventually you'll want to tear down the small towns to allow big cities to flourish. 

ANother addition that would be cool is if cities could grow together - two small towns that physically join could become one larger town.

Come to think of it, if you use the city "influence" approach, there's no real reason to require built tiles to be physically adjacent.  If you want to put your farms several tiles away, go for it.  It'll mean your defensive forces have farther to go if someone moves in and starts burning them, but it may allow you to take advantage of natural resources.  That's the usual reason cities had outlying orchards, farms, mines, etcetera. 

For that matter, why not have an inn three tiles away from the city center? 

And why not using the lore to prevent city spamming ? Each turn, cities can lose some of their people due to radiations, earthquake, marauders, trolls, spiders, any nasty thing you can think of. So you would need to carefully prepare each of your new city. I would love to play versus other players AND versus the earth.

No, a small city wouldn't be able to produce units as quickly as a large city.  You'd have 5 cities that produce units very slowly as opposed 2 cities that can produce them quickly.

No, if you have 10% population grown, a large city of 500 gains 50 people.  5 small cities of 100 people gain 10 people each, or 50 people.

It's actually very, very easy to prevent city spamming if there is a food cap.  Just make larger cities more efficient per citizen or have greater synergistic benefits between industry when inside a city.  One school would give you +10 research points and +3 for each additional school.  Just an example.  If food limits population and food is limited, then there will only be so much population.  If there is an efficiency equilibrium that is skewed toward larger cities, then most population will be clustered in larger cities.  It's that simple.

Now, please understand that nothing but big cities would always be the solution.  In most circumstances, though, this would be the more efficient route.  Sure, a player could still spam cities if they wanted to every game, but it would be a losing strategy.

@cauldyth. humm .. you're right about unit producing. But in the long time 5 cities will be better then 2 cities. But for population growth you forget to add the prestige bonus ! A city of 500 and a pop growth of 10% would get 50 more pop and a percentage due to prestige. And prestige doesn't automatically grow. So 5 cities will get you more prestige than one city, unless you build a lot of prestige buildings in your only town. Another thing also in favor of 5 city vs 1 : you get more tiles to build on, due to the cap in buildable tiles.

Oh come on this is a distraction.  The game is in development.  Population growth is whatever the hell the devs want it to be.  These things aren't immutable.  Want 5 cities to grow slower than 1 big city at the beginning?  Easy, make it that way.  There are tons of mechanisms to make that happen.  Make them more vulnerable, give them a prestige penalty, etc.  Want to change the city tile cap now that food is limited and, thus population is limited?  Lift the tile cap. 

Now, I know what you are going to say.  "So why don't players just stick with one big city and never build smaller ones?"  Simple.  If you only have big cities, you have less variety in resources.  

Honestly I think this is a bad idea. It doesn't address the fundamental problem which is city-spam = good. Also it's arbitrary. It takes away the choice from the player rather than making the choice of not spamming cities strategically viable. If you want people to build RPG-esque kingdoms then you need to make RPG-esque kingdoms MORE strategically advantageous than spammin large cities.