A nice overall summary of the types of economy in FfH2
. I find the Trader Economy in FfH2 is very different from the one in BtS due to the larger number of trade routes and the higher costs of buildings.
Trader Economy
Less well known and more specialized, the Trader involves a lot of cities with a lot of trade routes. This works particularly well on maps with lots of ocean, even if you are not the Lanun. You will want to aim for Cartography, Trade and Currency to gain the optimum benefit from this economy. Wonders such as The Great Lighthouse are also helpful. This economy works well for Organized and Expansive leaders. Organized leaders pay less on civic upkeep, which will increase with your amount of cities. Expansive leaders can quickly build settlers to get more cities out there.
This economy is NOT good for warmongering leaders, despite them having a lot of cities; you will need a lot of Open Borders for this to work. For this reason, the Eyes and Ears network might be a good wonder to aim for; you will have a lot of Open Borders anyway, and Inns which are requires for EaEN boost trade routes anyway.
I think this economy works well for a warmonger since internal trade routes have to make up the bulk of all trade once each city starts picking up additional routes. There are just not enough foriegn trade routes to service many of your cities. Also if you build a large empire I am not convinced that having open borders is that useful in relative terms, since the AI gains more commerce and at higher difficulty levels has substantial bonusses for research and unit upgrades. A warmonger can use trade routes as the basis of an economy that supports expansion in the middle game particularly if the bulk of cities are coastal (for more trade routes) and there are a few offshore city sites (for the 100% bonus). If you are going for a Trade Economy then there is a strong incentive to build cities on the coast even if there might be slightly better sites inland, the extra trade routes and the bonuses from harbour can make a coastal site much stronger in the long run.
Lastly, some notes on the trader economy
Every city starts out with 1 trade route, if it is connected to another city. Free trade routes can be gotten from the techs trade and currency, as well as from the overcouncil or undercouncil resolutions (overcouncil and undercouncil each allow +1 trade route resolution). Free trade adds +1 trade routes to all cities, with another +1 to coastal cities. Lighthouses grant +1 trade routes, as do inns and taverns. The great lighthouse adds +2 trade routes to all coastal cities. This leads to a possible 7 trade routes in all cities, and 11 in coastal cities.
Trade route income is determined by a number of variables. Population adds +.1 commerce per pop over 12 (iirc, I could be wrong here). This is added as a % multiplier in the city receiving the trade route, or as a +.1 commerce in the city providing it (that means that if the city with the trade route is providing it, all the other multipliers will effect that, not just multiplier from the city receiving it. Trade route income is increased +25% from connection to capital, from having an inn, and from having a tavern. It is increased by +50% from having a harbor. It is increased +100% from overseas trade, and 150% from prolonged peace (this is what makes foreign trade routes so nice). All in all, this means that a city can have +375% increase in trade route income, not counting population. That 375% is additive, meaning that a trade route providing 1 base commerce now provides 4 commerce (it is rounded down, always). Increase it by 25% due to population (30% actually, but you get the picture) and that is increased to 5 commerce. Lastly, if the city you're trading with provides 1.2 commerce base, that commerce is multiplied by 375%, then added, giving you 5.5 commerce base, or 5 commerce.
-Colin
Plenty of good information there
. I believe the trade routes work in the same way they do in BtS as far as the value of trade routes and so the same techniques I use there still apply. There are two things a player can do to boost his income from internal trade routes other than just increase their number. One is to establish at least some cities offshore (to get the 100% bonus) and the other is to grow some cities very large (to boost the base value of the trade route). A Trade Economy should try to do both to some extent.
I think of value of trade routes as the product of two independant factors, Factor A is the base value of the trade route and Factor B is the sum of the bonusses and the value of the trade route is then A x B rounded down.
Factor A, the base value of the trade route, is determined by the size of the sending city and the distance it is from the receiving city (where the trade route is). Basically it is the size of the city divided by 10, but has a minumum value of 1. So all cities smaller than size 10 count as if they were size 10. Large cities are much more valuable and a size 25 city has a base value of 2.5 for all internal routes that use it. This size factor is modified by a distance factor, which I forget the details of but it means that cities closer than about 16 tiles will treat a large city as if it was smaller in size. Distant cities will count the full size. A Trade Economy should try to build up the size of 4 or 5 of its core cities above size 20 so these can act as sources of commerce to the many other cities. A key point affecting Factor A is that foriegn cities can only be used by one of your cities and only gives 1 good trade route, whereas one of your own large cities can be used by many of your own cities and can give a lot more net income. In FfH2 paying attention to internal trade routes is much more important than foreign ones; and this is even more the case than it already is in BtS due to the much larger number of potential trade routes.
Factor B, is simply the sum of all the bonusses that apply to each trade route. Superficially, the best bonus is the the 150% for a foriegn trade route. But each foriegn city can only provide 1 trade route in 1 of your cities and some of those foriegn cities will be smaller than size 10 and only provide a basic 1 value route. If you have 20 cities requiring an average of 8 trade routes (say), then open borders with another civ with 6 cities will give you 6 of the 160 routes you need. On the other hand he will get 20 trade routes from you of the (say) 30 trade routes he needs. Obviously the other civ is gaining far more commerce from trade than you in this case. Maybe you don't mind that when you have 20 cities and he only has 6, but maybe you do mind he is using the extra commerce (multiplied by the AI bonusses) to research and then trading those technologies to a more powerful rival. Foriegn trade can be a two edged sword.
Internal trade is purely beneficial and can be used as an important part of the economy. The two ways to boost the value of Factor B for internal trade without buildings, are a) to build or capture some cities offshore (+100% bonus) and b) grow the size of own city (+5% for each citizen above 10). Let's consider an example. An offshore size 20 city will give a base value 2 internal trade route to most of your other cities that also get a +100% bonus, so they will each get at least 4 trade income and more if they are large or coastal themselves. The size 20 offshore city also gets a lot of valuable trade routes in return and they all have +100% for offshore and +50% (for its size 20). So if your capital is also size 20 this offshore city will get a base value 2 trade route; with a harbour (+50%) an inn (+25%) and connection to the capital (+25%) and +100% (offshore), +50% (size 20), which is +250% in total, then that internal trade route with the capital is worth 7 commerce. A little later in the game if the capital and the offshore city both grow to size 25 then the base value of the trade route grows to 2.5 and the size factor adds +75% (instead of +50%), add a tavern for another +25% and we get 2.5 for Factor A and +300% for Factor B (remember we already have 100%
) so the internal trade route is now 10 commerce and better than most foriegn trade. This is how several large cities in FfH2 can build up very lucrative trade routes between themselves as long as they are far enough apart. Spreading out large cities and locating them on separate landmasses can make a very strong economy based on internal trade. Note these big cities will also supply valuable trade routes to many other smaller cities in the empire although they won't be as valuable due to lower size and less infrastructure, but they are essentially free.
Several buildings can boost trade routes but as with all buildings in FfH2 they are expensive in hammers and need to be carefully balanced with other uses for those hammers. A warmonger should consider whether more units are needed and whether other buildings are better for the economy (e.g. a market, courthouse, gambling house). For coastal sites the lighthouse (160
) and harbour (120
) are pretty much essential and cost effective for other reasons that can justify building them. The inn and tavern are another matter and at 250
apiece are probably only worth building in a few cities, as each inn costs the equivalent of 2 champions. I tend to build them in cities that are already very large where the extra trade route is useful and in coastal cities that already have a lot of trade routes where the +25% bonus will help boost some existing trade routes. These high hammer cost means that many of my cities are not fully developed to maximise their trade potential.
Incidentally, the name Trade Economy is a bit of a misnomer as other sources of income will be combined with it and can even produce more than the trade component. For instance elves could combine income from cottages in their giant sized FoL cities with trade routes. And a Financial leader working many coastal tiles can get more commerce early on from that source before the trade routes are built up since these require quite a lot of expensive infrastructure to reach their full potential. The basic principles of the trade still apply and all cities get some income from trade, the question is whether it is worth trying to develop that part of the economy or another. Particularly, I often find it hard giving up the extra food from Agrarian to adopt Foriegn Trade just for the extra routes. The extra food from Agrarian can mean bigger cities (and hence better trade routes) and the -10% gold multiplier can be painful making it a weak civic even in an economy set up to use the potential of trade.
EDIT: A good reason for a warmonger going for domination to use a Trade Economy on a map that has plenty of water is the Nexus (requires Pass through the Ether). This is an astonishingly powerful late game wonder that adds an Obsidian Gate to each city and that adds yet another trade route. So as well as allowing much easier movement of units between cities there is a massive boost to the economy and a Trade Economy makes the most of that bonus.