Choice of terrain | Battle Total War: Attila Guide
Last update: 11 May 2016
There are six terrain types on which land battle that isn't a siege might play. In case of naval battles this number drops to three.
Plain is a perfectly flat terrain with single groups of trees. It is the only place where you can hide, everywhere else formations are easily visible. If the weather is good, immediately after battle starts both sides should see their formations and reinforcements. Plains are perfect for cavalry, as they allow it to easily maneuver and gain speed for charge. For infantry and other unit types conditions are good, but not perfect. Especially for shooters and siege machines, that can't take higher positions, but aren't forced to shoot from the bottom of a hill as well. Battle editor has an additional position cobblestone, but it is practically a plain that have a road through whole map and less flat territory.
Swamp is different from plain in having many places that make it harder to move. A formation marching through swamp receives a 50% penalty to movement speed and charge bonus. It's a perfect place to fight for missile units. You must simply block the main passage with infantry, forcing enemy to break through spearmen formation or walk through swamps, under archers and machines fire. Cavalry have hard times on the swamps as well, as its main advantages, mobility and charge, are greatly limited.
Woodland is similar to swamps, but with three differences. First, woodland is usually larger than swamps, which makes it impossible to block it. Second, moving through woodland have 75% penalty to speed, not 50%. In other words, cavalry will work better in woodland than in swamp. Third, forest allows hiding. Most formations become invisible in forest until enemy approaches them. It allows creating ambushes and shooting enemy positions without worrying of immediate counterattack.
Battle editor used Pyrenees name to describe mountain territory. A great place to fight for shooters and infantry protecting them, far worse for cavalry that won't be able to gain proper speed when riding up. A territory that favors defenders, much harder for attackers.
River crossing battle is practically two plains separated with water. Both territories are connected only with bridges and footbridges, passing the water in other spots is impossible. It makes rivers perfect place for defense if you manage to block both passages and won't enemy attack you from the back. Passing through river is especially dangerous because of its narrowness and 50% penalty to moving speed. Infantry with the backup of archers can change it into a dangerous trap.
In case of naval battles, you have a simple choice. You can fight on open sea, with even a small fragment of land, or at coastline. The first is practically a plain filled with water, the latter can be both gentle and very bluff. Amount of spots where you can land depends on the coastline. It is especially important in case of mixed battles, when you want to support your land forces with warriors that are on the sea.