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Gravel Source—Pueblo Area,Colorado,Parts of Pueblo and Custer Counties Two Rivers Pit <br /> Aggregation is the process by which a set of component attribute values is <br /> reduced to a single value that represents the map unit as a whole. <br /> A map unit is typically composed of one or more"components".A component is <br /> either some type of soil or some nonsoil entity, e.g., rock outcrop. For the <br /> attribute being aggregated, the first step of the aggregation process is to derive <br /> one attribute value for each of a map unit's components. From this set of <br /> component attributes, the next step of the aggregation process derives a single <br /> value that represents the map unit as a whole. Once a single value for each map <br /> unit is derived, a thematic map for soil map units can be rendered.Aggregation <br /> must be done because, on any soil map, map units are delineated but <br /> components are not. <br /> For each of a map unit's components, a corresponding percent composition is <br /> recorded.A percent composition of 60 indicates that the corresponding <br /> component typically makes up approximately 60%of the map unit. Percent <br /> composition is a critical factor in some, but not all, aggregation methods. <br /> The aggregation method"Dominant Condition"first groups like attribute values <br /> for the components in a map unit. For each group, percent composition is set to <br /> the sum of the percent composition of all components participating in that group. <br /> These groups now represent"conditions"rather than components. The attribute <br /> value associated with the group with the highest cumulative percent composition <br /> is returned. If more than one group shares the highest cumulative percent <br /> composition, the corresponding "tie-break"rule determines which value should <br /> be returned.The"tie-break"rule indicates whether the lower or higher group <br /> value should be returned in the case of a percent composition tie.The result <br /> returned by this aggregation method represents the dominant condition <br /> throughout the map unit only when no tie has occurred. <br /> Component Percent Cutoff None Specified <br /> Components whose percent composition is below the cutoff value will not be <br /> considered. If no cutoff value is specified, all components in the database will be <br /> considered. The data for some contrasting soils of minor extent may not be in the <br /> database, and therefore are not considered. <br /> Tie-break Rule: Higher <br /> The tie-break rule indicates which value should be selected from a set of multiple <br /> candidate values, or which value should be selected in the event of a percent <br /> composition tie. <br /> USDA Natural Resources Web Soil Survey 12/30/2023 <br /> Conservation Service National Cooperative Soil Survey Page 7 of 7 <br />