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Offline Carl

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Tiny cities with huge populations
« on: June 24, 2010, 10:46:39 AM »
I've been trying to generate maps with very large cities (several hundred thousand citizens). Sometimes when I generate these maps in Experimental I get tiny cities (by area -- say 6x6 squares) with huge populations. Sure, they are densely populated, but there are plenty of other cities on these maps with huge densely populated areas but with much smaller populations.

I'm not certain that this is specifically an Experimental issue, but I haven't encountered it in the main version. I should note that I have the new "density regulator" option in simuconf turned off.

Is this a bug? What causes it?

Offline jamespetts gb

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Re: Tiny cities with huge populations
« Reply #1 on: June 24, 2010, 12:03:20 PM »
Jha,

welcome to the forums! Thank you for your interest in Simutrans-Experimental. High density cities can be caused by cities being built in difficult terrain where it is not easy to expand. In recent versions of Simutrans-Experimental, there is also a change to the way in which city density is calculated, such that settings in paksets governing city density may be non-optimal (however, that would tend to result in lower, rather than higher, densities).

Might I ask: what pakset are you using? What is the "renovation_percentage" in cityrules.tab?

Offline Carl

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Re: Tiny cities with huge populations
« Reply #2 on: June 24, 2010, 03:35:25 PM »
Thanks for the welcome!

To clarify, the issue was not the density per se, but rather the fact that a city measuring only 6x6 was recorded as having 450,000 inhabitants while larger and just as dense cities had lower populations.

I'm using pak64, and Renovation percentage is 12.
« Last Edit: June 24, 2010, 03:58:57 PM by jha4ceb »

Offline jamespetts gb

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Re: Tiny cities with huge populations
« Reply #3 on: June 24, 2010, 03:58:17 PM »
I have not noticed this issue before. What were the "unemployed" and "homeless" numbers in these cities, and what version of Experimental are you using?

Offline Carl

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Re: Tiny cities with huge populations
« Reply #4 on: June 24, 2010, 04:02:19 PM »
The version is 102.3 8.1.

I've just recreated the problem on another map. I have a tiny city with 7 buildings and a population of 4,144,872. Not surprisingly, 4,143,632 of those are homeless and 4,143,592 are unemployed.

Offline jamespetts gb

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Re: Tiny cities with huge populations
« Reply #5 on: June 24, 2010, 10:34:46 PM »
Hmm, this is rather odd. Can you let me know what map generation parameters that you were using?

Offline Carl

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Re: Tiny cities with huge populations
« Reply #6 on: June 26, 2010, 01:29:14 PM »
Mostly, the problems occurred when using very high median city sizes - 200,000, 400,000. But I've also noticed them occur with lower median sizes, e.g. 10,000 and 20,000.

Sometimes it seems like the game has generated a city in a particular spot, but then found that it does not have sufficient space to make a city of the size required to house so many people -- so we end up with a small-sized city with many homeless But since I have no knowledge of the generation process, this is just a hypothesis.
 

Offline jamespetts gb

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Re: Tiny cities with huge populations
« Reply #7 on: June 26, 2010, 01:41:55 PM »
Mostly, the problems occurred when using very high median city sizes - 200,000, 400,000. But I've also noticed them occur with lower median sizes, e.g. 10,000 and 20,000.

Sometimes it seems like the game has generated a city in a particular spot, but then found that it does not have sufficient space to make a city of the size required to house so many people -- so we end up with a small-sized city with many homeless But since I have no knowledge of the generation process, this is just a hypothesis.
 

Ahh, I suspect that your hypothesis is correct. It is very unusual to have median city sizes in five figures, and the city building routine is indeed limited by terrain. This is not, therefore, a Simutrans-Experimental specific issue.

Offline Dutchman on Rails

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Re: Tiny cities with huge populations
« Reply #8 on: June 27, 2010, 09:55:14 AM »
I've seen this kind of problem before. In my mountainous terrain, sometimes cities end up boxed in (no more roads can be built without raising or lowering land. The town continues to grow, but (almost) all of the citizens are added to the homeless pool. As far as I can tell, there is no check to stop city growth if the number of homeless becomes too great.

The workaround I found was to raise/lower strategic corners of the land so that the town can build roads on the newly created flat land/slopes. After that it should expand to accommodate the homeless people.

Offline Carl

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Re: Tiny cities with huge populations
« Reply #9 on: June 27, 2010, 09:56:34 AM »
That seems like a good strategy.

Also, I think I should stop trying to generate maps with very large cities!

Offline Dutchman on Rails

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Re: Tiny cities with huge populations
« Reply #10 on: June 27, 2010, 10:24:52 AM »
Maps with large cities should be alright, but... As long as there's no cap on the homeless number prohibiting growth, they need the room to expand. If you keep your cities spaced well apart and in fairly flat landscape, they should have plenty of room to expand into.