Page:Geographic Areas Reference Manual (GARM).pdf/272

 Table 11-1. Hierarchy of Census Feature Classes for Use as Block Boundaries Qualifying features ranked from highest to lowest priority: 11-12Census Blocks and Block Groups
 * 1) Must-hold census block boundary (see “” section)
 * 2) Water area (double-line drainage)
 * 3) Named, addressable divided roads (by road class)
 * 4) Named, addressable undivided roads (by road class)
 * 5) Unnamed addressable divided roads (by road class)
 * 6) Unnamed addressable undivided roads (by road class)
 * 7) Other addressable features
 * 8) Feature extensions (manually inserted)
 * 9) 1980 statistical/governmental unit boundary (by category)
 * 10) Main rail line feature
 * 11) Railyard
 * 12) Rail spur and other rail feature
 * 13) Named perennial stream (single-line drainage)
 * 14) Power transmission line
 * 15) Pipeline
 * 16) Unnamed perennial stream (single-line drainage)
 * 17) Named perennial or unclassified canal, ditch, or aqueduct
 * 18) Unnamed perennial or unclassified canal, ditch, or aqueduct
 * 19) Named intermittent stream or wash (single-line drainage)
 * 20) Named braided stream (single-line drainage)
 * 21) Unnamed braided stream (single-line drainage)
 * 22) Named intermittent canal, ditch, or aqueduct
 * 23) Topographic feature (such as bluffs, cliffs)
 * 24) Fence line
 * 25) Point-to-point line
 * 26) Feature extension, other than manually inserted extension
 * 27) Other special transport feature
 * 28) Physical feature not listed