Freehand Rule

Freehand rule is flexible and can express a relationship that is very complex. It is possible that none of bell-shaped, Z-shaped and S-shaped can effectively express the relationship. For example, there might be more than one ideal conditions, so the curve may have more than one peak. To support this kind of knowledge, we need a freehand rule.

A freehand rule is used when soil scientists can provide some key points whose optimality value are known. If three or more key points are provided, the program will interpolate these points into a curve using cubic spline function.

When the key points are deleted, modified or moved, the curve will change accordingly. Soil scientist can keep adjusting the curve by deleting or/and moving the points until they are satisfied with the result.

To define freehand rules,  at least three key points should be provided so that SoLIM Solutions can interpolate them into a curve.