Overriding Inherited 'Attribute' Components
Not only can we unambiguously specify an ECC_TREED_TRACT <Polygon> in an ECC_TERRAIN <Union Of Primitive Geometry>, but we can override other inherited information as well.
No conflicting attributes may be specified at the same level of the tree, but if a different value for an attribute is specified at a lower level, it is considered to override the inherited value.
meaning = { SE_ELEM_CODE_TYP_ATTRIBUTE, { EAC_VEGETATION_TYPE }}
value_unit = EUC_UNITLESS
value = { SE_PDV_ENUMERANT_CODE, { EEC_VEGTY_BLACK_SPRUCE }}