The Crusader Editor: The Watering Hole
Perhaps the biggest change in Crusader is the requirement to build all farm buildings (except Hunting Posts) on Oasis Land.
The first thing that should be emphasized here is that this is not true. If you look at your list of available lands, you will see Oasis, but you will also see two types of scrub land. Farm buildings can, in fact, also be placed on the Thick Scrub terrain just as well as on Oasis land. This is helpful for a few reasons. First, it lets you create a bit of a hazy border to the oasis, so that a farm only needs to be partially on the oasis proper. It also lets you create an area that doesn't look as lush as an oasis, but can fill the same purposes.
There is another big change that may not be immediately apparent in Crusader. Back in Stronghold, it was a simple fact of life that farms had to be placed on the lowest terrain level. This is no longer the case. Farms can be placed on any patch of oasis or thick scrub large enough to contain them, and those terrains can be placed on level terrain at any height. They will not, however, place on hilly terrain, there must be either a valley or plateau of some kind.
Placement of Oasis is difficult at first, especially in determining the size which you want to use. In my first expirements with Oasis, I constantly made them too small, or accidentally left holes of desert terrain that made sections unbuildable. The way I found to combat these problems was to switch back and forth between terrain editing and building placement to make sure I could lay down the number of farms I was aiming for. As you get more accustomed to this new requirement, it will become easier to estimate the sizes. If you do want to use this method for determining oasis size, however, make sure that you have not yet placed Keeps and Stockpiles, so that the profit from deleting the farms is not added to the resource pile.
Oases also provide a challenge when balancing scenarios. Smaller
resource sections, such as iron and stone, can be easier to
mirror for all players in a balanced map, but oases are usually
larger, and their borders are less definate. Lacking a tool to
copy terrain, it is thus necessary to use other methods to make
sure that one player does not end up with more farmland than
another. One way around this would be to carefully place the
terrain tile by tile in the exact same pattern for each player.
This is tedious, and prone to mistakes. It is also possible to
use the same farm placement technique outlined above, doing it
once for each player's oasis.
Unfortunately, there's not going to be a fool-proof method for perfectly balancing the oases, so it may come down to just eyeballing, guessing, and hoping that the lands are not too far out of balance. Minor differences will be covered up by a player's skill in farmland management in most cases, so exact precision is not a necessity, but approximate precision should be aimed for in any map tagged as balanced.
* denotes a former staff member.