The distribution of land types, as calculated by the land type assignment algorithm, is dependent on the value of several parameters and coefficients, listed below. These settings are accessed from the parameters tab of the land type editor dialog, as seen below.

The base score value is the default 'score' of the land type in the land type assignment calculation. The various other coefficients add to or subtract from this score. The Base score is modified by the altitude range values, such that the land type has an effective base score of 0 outside the defined altitude bands.

Typically the base score is set so that the maximum score of a land type is around 100. For example, a grass land type with a water coefficient of 20 (and 0 for other parameters) would be given a base score of 80, and so the 'high score' of this type would be 100. This is not a hard-and-fast rule, but merely a guideline for saving sanity.

The gradient coefficient determines how the score of a land type changes with the gradient (or steepness) of the terrain. The gradient coefficient is usually high for cliffs (say ~100), zero for grass, and negative for land types that are not usually found on slopes, such as sand.

The curvature coefficient determines how the score of the land type changes with curvature (or 'bumpiness'). Normally the curvature coefficient is set to zero, but on rocky rocky terrain types it may be positive, and on loose/sandy/snow land types it may be negative.

The water coefficient determines how the score of the land type changes with the water-level in the water map. Typically values for some land types are:

The salinity coefficient determines how the score of the land type changes with the salinity in the water map. For most land types, this will be zero. This can however be positive for land types that are only found near the sea (e.g. beach sand) and may be negative for land types that are only found away from the sea (e.g. lake mud). The effect of the salinity coefficient is to increase the water coefficient in areas where the water map has high salinity (see salinity map). The salinity coefficient has no effect if the water coefficient is zero.

A recommended method of setting the value of land type coefficients is provided in the making a new climate tutorial. Two things to note from that tutorial are that:

1. Most land types will have only a few non-zero coefficients, as otherwise it becomes very complicated.
2. The actual values of these coefficients is somewhat irrelevant, as it is only the relative differences between land types that makes one land type score higher than another. Just how you balance these coefficients is a matter of taste.