Appendix C:  Glossary

rule: A rule is a function defining the relationship between the values of an environmental feature and the optimality values for a soil type.

 
instance: An instance is a representation of the soil scientist's knowledge of the relationship between a soil type and its environmental conditions characterized by topography, geology, climate, vegetation, and other environmental variables. It is not explicitly location-specific and is applicable to the whole mapping area, thus is usually considered to be the global knowledge. Note that a given soil type might appear in several instances, for example, a soil type may occur on both south facing and north facing slopes with different elevation and slope gradient conditions. These two environmental configurations form two instances of the soil. Technically, an instance refers to an environmental configuration defined by one or more rules, each of which corresponds to one environmental variable and characterizes the relationship between the optimality of the soil type and the environmental variable.

occurrence: An occurrence is a positive exception, which means a particular soil will occur in places where the global knowledge does not cover. It is a representation of the soil scientist's knowledge of the relationship between a soil type and its environmental conditions characterized by topography, geology, climate, vegetation, and other environmental variables within limited geographic area. The area is called "influenced area" in SoLIM Solutions. In the influenced area, the relationship between soil type and the environment is different from other places. The influence area is defined by a central location and a impact radius. Technically, in SoLIM Solutions, an occurrence consists of one or more rules (rule part) and a spatial setting.  When creating occurrences, the soil scientist needs to define rules that characterizes the relationship between the optimality of the soil type and the environmental variable. Besides, they need to pinpoint the coordinates of central location and provide the impact radius and a distance decay factor which determines how the optimality value will change as the distance to central location changes.

exclusion: An exclusion is a negative exception, which means a particular soil will be very unlikely to occur in some places where the global knowledge does cover.It is a representation of the soil scientist's knowledge of the relationship between a soil type and its environmental conditions characterized by topography, geology, climate, vegetation, and other environmental variables within limited geographic area. The area is called "influenced area" in SoLIM Solutions. In the influenced area, the relationship between soil type and the environment is different from other places. The influenced area is defined by a central location and a impact radius. Technically, in SoLIM Solutions, an exclusion consists of one or more rules (rule part) and a spatial setting.  When creating exclusion, the soil scientist needs to define rules that characterizes the relationship between the optimality of the soil type and the environmental variable. Besides, they need to pinpoint the coordinates of central location and provide the impact radius and a distance decay factor which determines how the optimality value will change as the distance to the central location changes.

soil type: A soil type corresponds to a named soil and contains instance(s), occurrence(s) and exclusion(s). In many cases there will be only one instance for a soil type, but in some cases there might be multiple instances or even occurrences and exclusions for a single soil type.
 
knowledge base: A knowledge base is a collection of soil types.  It is supposed to be created for a certain mapping area and contains all the soil types existing in the mapping area.

global knowledge: Global knowledge refers to the knowledge that is effective in the whole mapping area. In SoLIM, global knowledge is expressed as instances. Each instance is a representation of the soil scientist's knowledge on the relationship between a soil type and its environmental conditions. An instance contains one or more rules.

local knowledge: Local knowledge refers to the knowledge that takes effect within limited area. In SoLIM, local knowledge is expressed as occurrences and exclusions. An occurrence is a positive exception, which means a particular soil type will occur in places where the global knowledge does not cover. An exclusion is a negative exception, which means a particular soil type will be very unlikely to occur in some places where the global knowledge does cover. An occurrence/exclusion contains one or more rules plus spatial setting which defines the area being influenced.