Terrain. This adjustment is the only one in which there may be two components which are
added together, first, before the final result is multiplied alongside any and all other adjustments.
- Base terrain type. The defender receives an adjustment determined by the base terrain of the tile on which it is located. The amount of the adjustment is defined in the @TERRAIN section Rules.txt for each terrain type; it may be less than 1 (i.e. a penalty), equal to 1 (no effect), or greater than 1 (i.e. a bonus) depending on that value. Furthermore, TOTPP supports two additional configuration elements. If the defender's domain is 1 (Air) and the @COSMIC2 section contains the "TerrainDefenseForAir" key set to 0, then the adjustment is automatically equal to 1 (meaning the terrain has no effect). Similarly, if the defender's domain is 2 (Sea) and the @COSMIC2 section contains the "TerrainDefenseForSea" key set to 0, then the adjustment is automatically equal to 1 (meaning the terrain has no effect). Correctly documented in (3)(d)(i) through (iii), other than TOTPP support for suppressing the adjustment in certain situations. Also, the reference there implies that terrain factors are static and doesn't note that they are configurable for each terrain type, although this is widely known.
- River. If the tile on which the defender is located contains a river, the amount of the terrain adjustment is increased by 0.5 (as noted above, this is an addition that occurs as part of the calculation of the terrain adjustment, before it is multiplied with other adjustments). Note that the @COSMIC2 keys referenced in the previous point do not eliminate the river bonus. Correctly documented in (3)(d)(iv), except that a "%" sign should not be included near the end of the line.