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Surface Texture-San Miguel Area, Colorado, Parts of Dolores, Montrose, and <br />San Miguel Counties <br />J-Bird Mine Site <br />The aggregation method "Dominant Condition" first groups like attribute values for <br />the components in a map unit. For each group, percent composition is set to the <br />sum of the percent composition of all components participating in that group. These <br />groups now represent "conditions" rather than components. The attribute value <br />associated with the group with the highest cumulative percent composition is <br />returned. If more than one group shares the highest cumulative percent <br />composition, the corresponding "tie-break" rule determines which value should be <br />returned. The "tie-break" rule indicates whether the lower or higher group value <br />should be returned in the case of a percent composition tie. <br />The result 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: Lower <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 />Layer Options: Surface Layer <br />For an attribute of a soil horizon, a depth qualification must be specified. In most <br />cases it is probably most appropriate to specify a fixed depth range, either in <br />centimeters or inches. The Bottom Depth must be greater than the Top Depth, and <br />the Top Depth can be greater than zero. The choice of "inches" or "centimeters" <br />only applies to the depth of soil to be evaluated. It has no influence on the units of <br />measure the data are presented in. <br />When "Surface Layer" is specified as the depth qualifier, only the surface layer or <br />horizon is considered when deriving a value for a component, but keep in mind that <br />the thickness of the surface layer varies from component to component. <br />When "All Layers" is specified as the depth qualifier, all layers recorded for a <br />component are considered when deriving the value for that component. <br />Whenever more than one layer or horizon is considered when deriving a value for <br />a component, and the attribute being aggregated is a numeric attribute, a weighted <br />average value is returned, where the weighting factor is the layer or horizon <br />thickness. <br />USDA Natural Resources Web Soil Survey 2.1 12/24/2008 <br />Conservation Service National Cooperative Soil Survey Page 4 of 4