Blue Circles and HIdden Resources

[Bradlius]

I know that the computers suggests city sites with a blue circle, based almost solely on resources within an implied BFC. But does it take into account resources (iron, oil, aluminum) that might not be revealed yet? Or does it decide purely on what's visible?

 

[Excl]

I don't know, but it would be easy to find out. Start a game and go into map editor. Lay down a bunch of flat grass land and put one food resource on the four edges of your fat cross. (2 spaces north of settler, 2 spaces east, 2 spaces south, and 2 spaces west) Then put an oil, aluminum and uranium resource on the three squares just west of your western fatcross border.

Start the game and see if you get a blue circle where you're standing, or one square over.

 

[CivMonger]

that would explain some of the weird city placements I've been getting suggested to me lately.

 

[flanflan]

From my experiences I honestly believe this is true, because in some instances I placed my city right next to a recommended city spot, and later I find out that iron was placed a plot away from me. A plot too far away to receive the bonuses it offers to a city in their city radius... ;_;

 

[KMadCandy]

barbarians play by different rules of course. but they apparently do know where all the resources are. i'm sometimes very impressed by their city placement. they take into account the fat cross, even tho it's a long time until they get the culture pop. this is a city i captured from them in a recent game, when all i could see were the 3 food resources and the dye. i didn't have steam power yet, so that coal was a great surprise.

it was exactly where i'd have put it, even down to an easily irrigatable rice and not stupidly off the resources to get hill defense. it was farther from my core than i'd usually have gone that early, but i just could not resist.

i really do wonder what the game figures in the blue circle suggestions for players and the normal AI civs. but i CBA to play with WB and make a guess atm.

 

[Excl]

Resources that haven't been revealed yet have no effect on the blue circle.

I created the scenerio in the map editor where four resources were visible in the fat cross, while three "soon to be revealed resources" sat just to the north, and three "advance technology resources" sat just to the west. The game suggested that I build in between the four original resources and gave no suggestion to build close to the future resources:

 

[Defiant47]

Resources that haven't been revealed yet have no effect on the blue circle.

I created the scenerio in the map editor where four resources were visible in the fat cross, while three "soon to be revealed resources" sat just to the north, and three "advance technology resources" sat just to the west. The game suggested that I build in between the four original resources and gave no suggestion to build close to the future resources:

Keep going. Now test what happens if you give yourself BW and IW. How will the circle change? (of course explore that way first as well)

Now take away BW and IW and give yourself the technologies to discover the resources to the west.

What happens?

 

[flanflan]

I dunno. Even if it's proven that the blue circle doesn't take account into future resources I'd still build them there or occasionally stick with my original plan of building it elsewhere.

 

[JimT]

Resources that haven't been revealed yet have no effect on the blue circle.

I created the scenerio in the map editor where four resources were visible in the fat cross, while three "soon to be revealed resources" sat just to the north, and three "advance technology resources" sat just to the west. The game suggested that I build in between the four original resources and gave no suggestion to build close to the future resources:[/img]

But you haven't explored the territory to your North. Are you sure your experiment hasn't shown the circles ignore unexplored resources but not neccessarily invisible resources.

JT

 

[wioneo]

Why don't you just fill in 20 grassland squares in the form of a fat cross with aluminum and see if the blue circle apears in the middle?

 

[Excl]

But you haven't explored the territory to your North. Are you sure your experiment hasn't shown the circles ignore unexplored resources but not neccessarily invisible resources.

Although I didn't take a screen shot of it, I did try this. I had four scouts with the explorer and used them to reveal the terrain. It did nothing to change the placement of the blue circle.

 

[Shoot the Moon]

Do blue circles take into effect resources hidden in the fog? I am pretty sure at one point they did (I remember reading a thread about it), but this might have been fixed in a patch.

 

[Excl]

Okay, I've got some extended research here. I've been able to determine a few things, and I've got some screenshot explainations below for each point.

The rules I've been able to determine are:
1) Undiscovered terrain doesn't seem to have an effect on blue circle placement.
2) Circle placement is recalculated AFTER each turn, so if you discover Iron Working one turn, you won't get accurate city placement suggestions until the next round.
3) You have to discover the tech first before the city placement suggestion is adjusted.



Here's my little experiment:

I started off with a random Civ and immediatly got three suggestions for my city. If you notice, two of them are away from what I can see, so it must be suggesting placement for resources I've yet to uncover in the fog.

I've now entered map mode to reveal that there is infact some resources that are outside the tiles I've been able to view, yet I'm still getting a suggestion for them. There are a few "future tech" resources nearby, but I'm not positive that the city placement is getting effected by this just yet. More on this later.

In this next shot, I've completely removed everything nearby and replaced it with flattened grassland, so terrain will have no effect on the city placement suggestion. I've placed four resources available at the start of the game at each of the four sides of my fat cross. I've also placed three resources that will get revealed shortly in the game to the north (copper, iron, horses) ... As well as three distant future resources to the west (aluminum, uranium, oil). If city placement is effected regardless of what techs I have, then I should get a suggestion much further to the north and west of where my settler is at currently.

I've returned to playing mode, and you can notice right away that the blue circles have not changed. I've used some explorers to help reveal a bit of the terrain. The circles are exactly where they were when I first entered the game.

I skip a turn with the settler and now the circles have readjusted. With nothing but the currect "game-start" resources showing (rice, sheep, dye, ivory), I only get a suggestion right where the settler is standing. The Iron/Copper/Horse is ignored to the north, as are the resources to the west.

I now grant myself all of the stone age and classical techs, which reveal the resources to the north. I skip a turn to get a new blue circle calculation. Notice below, how only the iron is revealed within the fog, yet the blue circle takes into account the other two resources to the north and suggests I build one square directly north. If it didn't take into account the fog-hidden copper and horses, it would of told me to build closer to the iron. It also still ignores the modern resources to the west.

I go back into the map editor and grant myself every technology. This reveals the entire map, but because I haven't advanced a turn yet, it still gives me the suggestion shown in the last screenshot.

I skip a turn, and now it reveals what we would expect if all resources were taken into account. The suggested circle is much closer to all the future resources, which may suggest that they get a bit of a preference over top of the older resources.

 

[ownedbyakorat]

I wonder if a potential city site being a plains hill affects the calculation.

Also I'd be interested in knowing whether fresh water, forests or flood plain health penalties affect it, too.

Nice experiments, keep it going please!

 

[Bradlius]

Wow, Excl. That's very thorough and certainly answers my original question. Thanks.

 

[BumpNsubz]

Absolutely great experiment. I'm still convinced that the AI knows something we don't though. I've seen time and time again where the AI builds a city far off from the capital with no reason and without resource revealing techs learned, to find out later that there is an iron or copper source right next to them. Maybe just circumstantial, but just seems fishy. I do believe however, the suggestion that we are given doesn't take this into account and only suggests what we know is there...thanks to Excl's demo.

 

[Elandal]

The AI doesn't have hidden resource information. That's one thing that changed from civ3. The AI doesn't actually cheat much, it just has quite high bonuses over human player - yes, it has bonuses on Noble already.

Barbarians do cheat though. They know the resources, and thus barb cities can grab a resource you will learn about in a millenium or two..

 

[Welnic]

Just one thing to add. The starting spot is a special place. There is a setting for each difficulty on how good the start needs to be. If the place that you are set down randomly does not have enough resources to meet these requirements, then things are changed until they do. This might include adding copper or iron to the BFC. This will not change the blue circle positions, but it is something to think about if your initial position looks like it lacks that certain something that would make it a good start.

 

[malekithe]

Notice below, how only the iron is revealed within the fog, yet the blue circle takes into account the other two resources to the north and suggests I build one square directly north. If it didn't take into account the fog-hidden copper and horses, it would of told me to build closer to the iron.

What makes you think it's taking the other two resources into account? Rather, why can't it simply be suggesting you settle in the only tile within range of the iron and 3 other known resources?

 

[Excl]

What makes you think it's taking the other two resources into account? Rather, why can't it simply be suggesting you settle in the only tile within range of the iron and 3 other known resources?

You're right, I was actually thinking about that after I had made my post. However, the original set of screenshots show that the circles take into account resources that haven't been revealed through the fog yet.