AI and poor colonization choices

[Finwelf]

Good day everybody.
I tried to search for a thread like that, but I failed, so sorry if it was already asked a thousand times already.

When I was testing some stuff today, I realised that AI makes really, really poor colonization choices. For example, take a look at the image below, in spoiler tags:

Spoiler

Florence, despite bordering uncolonised Rome, Siena and Naples (unshown on the screenshot) decided to colonise Cyrenaica instead. Choice may seem a bit odd, because well, the first three provinces are 28, 20 and 25 development each, but let's say it wanted to get a foothold in Africa to colonise provinces further south later on. However, the next choice is just stupid. Instead of colonizing Alexandria, which is 19 development, centre of trade and has a nice temperate climate, it literally decided to colonize a 1/1/1 arid desert without any provinces.
That's why I'm asking - what are exactly the AI priorities while colonizing? I hope it's a bug, because otherwise it would mean colonization is really flawed.

 

[khardinal]

Colonial maintenance is tied with province development, I think.
So a 19 Alexandria would be much much coster than a 3 province in term of colonial maintenance. Maybe the AI is calculating the cost, and compares it with its income

EDIT : If I understand the calcul, a 3 dev province would cost : 24 + 0.75 per year.
A 20 province would cost 24 + 5 per year.

 

[Finwelf]

Thanks, didn't know that.
I doubt it's this one though, since Tuscany had over 150 income a year (with 3 1/1/1 colonies) and this extra 4.25 is barely 0,37 extra expenses a month wouldn't be that much. Especially since it had 3 colonists and would reserve up to 24 ducats/month for colonizing.
Also, Byzantium colonised the province around 1595 despite much lower income (around 8/month).

 

[DanubianCossak]

It is also possible that an event that spawns colony fired for them, next time try to capture a screen shot of colonist on route to establish a colony, thats a way more definitive way to tell.

 

[khardinal]

Also, this colony has no natives at all. The AI definitely takes natives size, hostilness etc in consideration. What's the Alexandria situation ?

 

[Finwelf]

It is also possible that an event that spawns colony fired for them, next time try to capture a screen shot of colonist on route to establish a colony, thats a way more definitive way to tell.

I'm watching it in observe mode, and I couldn't capture the screenshot of the colonist en route, yet it had been over 50 years and there are quite a few nations in Mediterranean that have Alexandria in distance and hadn't colonised it.

Also, this colony has no natives at all. The AI definitely takes natives size, hostilness etc in consideration. What's the Alexandria situation ?

There were no natives.

 

[Chaingun]

I want to revisit the colonization code some time, not really highest priority of everything that should be improved though. AFAIK, (looked quickly at it a while ago) it was a lot related to trade nodes and how much AI thought the added trade would benefit it. Doesn't quite explain your scenario though.

 

[SuperBearNut]

What really irks me is that colonial Caribbean in my games always colonize Colombia instead of Caribbean. Every single game.

Basically colonial nations should colonize they region first.

 

[Finwelf]

I want to revisit the colonization code some time, not really highest priority of everything that should be improved though. AFAIK, (looked quickly at it a while ago) it was a lot related to trade nodes and how much AI thought the added trade would benefit it. Doesn't quite explain your scenario though.

Thank you for your answer, pity trade isn't the explanation.

What really irks me is that colonial Caribbean in my games always colonize Colombia instead of Caribbean. Every single game.

Basically colonial nations should colonize they region first.

Interesting enough, in this very scenario, New Netherlands, which is basically East Coast, did not colonise into Louisiana until it had no provinces left in it's own region. Same for Portuguese Carribean and Mexico (until the latter broke free and started colonising California).

A little update on development of situation - it's 1633 now, the Alexandria is still a part of Byzantium, but Cairo is still left uncolonised as an enclave between Byzies and Florence. Also, Bihar (a province in Hungary) and Linz (in Austria) are uncolonised despite the fact both border 3 countries, each with 3 colonists and no access to other colonies.
This led me to think, that AI may not colonise the province in fear of retaliationfrom other countries, but it's just a wild guess.

 

[Ex Mudder]

I want to revisit the colonization code some time, not really highest priority of everything that should be improved though. AFAIK, (looked quickly at it a while ago) it was a lot related to trade nodes and how much AI thought the added trade would benefit it. Doesn't quite explain your scenario though.

Main problem I saw was the +1000 (or so) AI weight for "adjacent to existing colony" leading to Portugal colonizing the whole of West Africa once they get 1 colony there. Check the AIveiw for wants to colonize, the weight for neighboring colonies is in the 900s, the rest are usually in the double digits. When they island hop, they often to do sensibly, until they make landfall, at which point they blob like a cancer.