Migration and Cities

[IsaacCAT]

Preface: In ancient Rome migration was very important and significant. I would argue it was the main drive for urban agglomerations.

Observation: In the game, migration is represented by the tribes migration mechanism and the POPS migration movement. The last one, I think is sorely lacking. On the other hand, building efficient cities is determined by population capacity, something that is at least artificial and very much exploited.

Suggestions:

• Scrap the population capacity limit, it is artificial and not useful. People will flock to cities no matter how many signs you put out there saying that the city is full.

• Big and crowded cities will have squalor, fires, diseases, etc... that will lower the migration attraction of the city momentarily, making POPS less inclined to migrate there and killing some POPS to cull the city. The player will be able to invest in some buildings to lower the chance of these bad outcomes for big cities, but they will never be 0%.

• Allow for migration to be a much broader phenomenon. Now it is almost a zero-sum game inside your provinces, where POPS are moved from your less attractive settlements or cities to your nicest cities inside the same province, with little interaction between provinces. I would like to see more migration between provinces, based on every province overall migration attraction. POPS all around the world shall migrate from unhappy, unstable, corrupt provinces to the next most attractive province. This will foster competition between nations, creating migration currents from less attractive provinces (far from the capital metropolis) to more stable and developed provinces (tall nations). To achieve this, all migrating POPS from one province will first migrate to bordering provinces with a significant higher migration attraction, if there are not, they will move as they do now. This migration attraction should be explained, e.g., we could have a ranking of provinces listed by their migration attractiveness, calculated as the sum of all of their cities and metropolis migration attraction.

• City and metropolis attraction could be improved with:
  • buildings and Wonders for greater migration attraction
  • trade, a developed city full of trade routes is more attractive than a city full of slaves
  • roads, rivers, and other modifiers also increase migration attraction as they do now.

I have borrowed the following ideas from the community and I want to acknowledge them:

Currently pops will only migrate further than 1 territory (or any distance within the same province) if their migration target is a port. There should be land based migration allowed between two territories at longer distances if the start and end points are connected by a road.

To prevent migration from being unreasonably long distance I would suggest restricting this somehow, either by weighting migration routes by distance (so that pops will tend to travel shorter distances even if there is a very favourable migration target a long distance away) or to simply put a hard cap on migration so that a pop will only ever migrate over land from one province to a neighbouring province. The latter seems like an easy and effective solution as it would avoid the possibility of weird edge cases and seems likely to result in a fairly natural gradual flow of population from the hinterlands into provincial cities and from there along road systems towards the capital or nearby major ports.

The main reasons I suggest this are as follows;

• Landlocked provinces tend to stagnate at the moment; inland cities absorb pops from their hinterland and then there is little movement of people thereafter
• Non-port capital cities are quite heavily penalised under the current system in terms of their ability to grow through migration
• It increases the value of roads and encourages roadbuilding, but still leaves ports as very powerful since they're both mechanically stronger and don't cost anything
• It has a pleasing sense of verisimlitude and gives another thing to play with for those of us who enjoy the "ant farm" aspect of the game watching population move around and do things in response to your actions

Since the initial post I have also thought that the addition of a similar feature to major rivers would be a good addition. There are currently many major rivers in game with few or no ports, and therefore these rivers don't have a significant role in the movement of peoples (adjacent territories do get a +1 migration attraction which is a minor bonus...). So to make major rivers - such as the lower Danube for example - into a slightly more "alive" feeling map feature I would suggest that any pop be able to migrate along the course of a major river to any other territory bordering the same river (this would be representing travel by boat so there would not be a cap on total distance and in this respect it would work very similarly to sea migration)

(edit: this was submitted on August 20 and was voted on enough to get third place in the SPQR that week)

Background - population efficiency and large cities:

After the changes to the population and trade systems in 1.5 its become clear that the way cities and their efficiency on population output grows has changed - but is still very significant and pretty much uncapped. Big cities are for sure fun, and to an extent, its good gameplay setting up the circumstances that allow them to grow and thrive in size & efficiency. it would probably not be fun to have their size capped in any arbitrary way. However, the lack of restriction s on city and province size beyond how much food you can import and how much you can grow your "population capacity" can end up crowding out other interesting uses of political influence, nation-building and the importance of provinces other than your capital. in 1.5, the limit of food-supply has actually been made more fluid and uncapped than before, since the higher class pops generate import routes that means they can "feed themselves" as long as food is available for import. The scaling of population capacity has become slower as the modifiers available are lower at the start of the game. The modifiers can still grow at a steady rate through province investments, however, and can still reach and exceed the point where the increase to the base pop-cap exceeds the 10 pop needed to unlock another building slot.

Justification / problem

The existing constraints to scaling of city-size and the productivity of these (capital) cities, lacks enough dimensions to make for a compelling balance throughout time and place in the game. countries who cant establish capitals and build cities in favourable locations with access to ports, decent civ value, technology and (ability to build) road networks will struggle to even begin scaling their cities, while civilized nations with access to these things can not only start scaling but reach a point of exponential scaling where other avenues of influence-expenditure and overall attention/investment are not worthwhile when compared to full attention and priority towards the capital city.

A way forward would be to add another dimension to the equation, one that has almost no effect on the smallest cities but a dynamically growing effect on the larger cities. Squalor.

I think adding a new dimension to how we make pops efficient can open more doors than it closes; it can open up more cool ways to rework/improve the trade system, reduce restrictions on the migration system, and more... (with significantly reduced proclivity for such changes to make the largest cities even more "unbalanced" in new ways)

Suggestion:



Large cities in ancient times were prone to get quite messy. I'm not the best informed around here when it comes to historical detail, but enough to find it a reasonable proposition that squalor might be an immersive concept to abstract and model for cities in the game. It seems ok to propose that cities could make room for A LOT people to settle and enable enough production & imports of foods to survive, but that at times, this would be done at a speed and scale that created ripples and problems for these cities and their social/political / economic interactions with their surroundings and overlords.

In terms of game mechanics, I'm sure professional game designers could come up with a neat system that fits with the existing systems in a good way better than I could, I'll just throw out a few rough ideas to tease the reader's mind:

Squalor-growth could be caused by

• the number of pops
• unrest
• low stability
• events
• more?

Squalor-impact could be

• Increased food consumption
• Reduced population output,
• Reduced population capacity, (!)
• Reduced migration attraction and increased migration speed (!)
• "Bad" events like fire/disease

Squalor-reduction over time could be caused by

• A base decay (resulting in low / no squalor for most settlements/cities under a certain size like <100-300 pops?)
• Granaries and/or other/new buildings
• Trade goods, reducing squalor produced by certain pop types, etc?
• A new governor policy? the existing decentralizing policy? certain
• Governor traits?
• Ruler traits?
• Laws? ideas? faction-interactions?
• Schemes for owners of the local holding?
• "Coordinate urban development" or similar city-level influence expenditure, scaling in cost if repeated.

This suggestion was brought to you by a previous discussion I had with @denkt2 on the wider topic.

Squalor and giving buildings provincial wide effect, as ways to make smaller cities more useful

The discussion in recent threads have been that the optimal way to manage cities is probably to only have a single city per province and make that city really large. This is mainly because how buildings only affect pops in the city they are built...

forum.paradoxplaza.com

... as always, I welcome any thoughts on the topic, and place your votes!
Thanks for reading!

Credit where is due, this suggestion arises from the post The good and the bad about Buildings: What do you build in your cities? from @Decius

My conclusion for that post is not new, @manager2525 on Jun4, 2020 already said on Minor issues (game tweaking) you would like to see addressed? that "Buildings strategy should be less gamey (All cities would need a forum, a temple, a theatre etc in order to keep citizens happy and increase migration)"

Thus, I want to bring the following suggestion to the Senatus Populusque:

1. Establish bonus for sets of buildings. For example:
   • Having a temple + tax office + Mill can provide a bonus to population migration and production. The set labeled "urbanized city"
   • Having a library + Court of Law + Forum can provide a bonus to research and migration. The set labeled "cosmopolitan city"
   • And so on
2. Provinces with a cluster of cities will have a bonus as well. Three cities in a province is an investment and demands food. The bonus could be tied to the label of the cities. For example:
   • 3 urbanized cities will have a bonus on population capacity
   • 3 cosmopolitan cities will have a bonus on invention cost
   • etc...

This will give an objective for different players:

• Min Max player will only get the best results with the bonus
• Empire builders or tall players will get a reward for their obsession

Having different sets allows for choice. Not doing any of the sets is also viable, as you can dedicate the resources (money and political influence) to expand wide.

 

[herrickrcw2]

I agree and it would be more historical accurate.

Rome had 1 million of inhabitants and there were may complaints about squalor and poverty.