Accessing & Using TIGER/DMD Files
-- Edges/Roads Shapefile Attributes
The Edges, or all lines, shapefile (edges.dbf) contains basic attributes of all roads and related lines (e.g., railroads). See Edges table/record layout below. Each edge has a unique TLID (TIGER/Line Identifier) value. The left and right faces for an edge can be determined by linking on the TFIDL (left) or TFIDR (right) attribute to the TFID attribute in the Topological Faces relationship table (faces.dbf).
The Address Ranges relationship table (addr.dbf) contains the attributes of each address range. Each address range has a unique ARID value. The edge to which an address range applies can be determined by linking to the edges shapefile on the TLID attribute. Multiple address ranges can apply to the same edge (an edge can have multiple address ranges).
The Address Range-Feature Name relationship table (addrfn.dbf) contains a record for each address range-linear feature name relationship. The purpose of this relationship file is to identify all street names associated with each address range. An edge can have several feature names; an address range located on an edge can be associated with one or any combination of the available feature names (an address range can have multiple feature names). The address range is identified by the ARID attribute, which can be used to link to the Address Ranges relationship table. The linear feature name is identified by the LINEARID attribute that relates the address range back to the featnames.dbf table.
The Feature Names relationship table (featnames.dbf) contains a record for each feature name-edge combination, and includes the feature name attributes. The edge to which a Feature Names relationship table record applies can be determined by linking to the All Lines shapefile on the TLID attribute. Multiple Feature Names relationship table records can link to the same edge, for example, a road edge could link to US Hwy 22 and Rathburn Road. The linear feature to which the feature name applies is identified by the LINEARID attribute. Multiple feature names may exist for the same edge (linear features are not included in the data set, but could be constructed using the All Lines shapefile and the relationship tables).
The Faces table (faces.dbf) contains the attributes of each face (side of edge). Each face has a unique TFID value. The face geometries can be built from the All Lines/Edges shapefile using the edge left and right face relationships. Each edge contains a TFIDL (left-side) and TFIDR (right-side) that can be used to link to the Faces TFID value.
The Area Landmark shapefile (arealm.shp) contains the geometry and attributes of each area landmark. Each area landmark has a unique AREAID value.
The Topological Faces-Area Landmark relationship table (facesal.dbf) contains a record for each face-area landmark relationship. The face to which a Topological Faces-Area Landmark relationship table record applies can be determined by linking to the Topological Faces relationship table on the TFID attribute. The area landmark to which a Topological Faces-Area Landmark relationship table record applies can de determined by linking to the Area Landmark shapefile on the AREAID attribute. A face may be part of multiple area landmarks. An area landmark may consist of multiple faces.
The Area Hydrography shapefile contains the geometry and attributes of each area hydrography feature. Each area hydrography feature has a unique HYDROID value.
The Topological Faces-Area Hydrography relationship table contains a record for each face-area hydrography feature relationship. The face to which a Topological Faces-Area Hydrography relationship table record applies can be determined by linking to the Topological Faces table on the TFID attribute. The area hydrography feature to which a Topological Faces-Area Hydrography relationship table record applies can be determined by linking to the Area Hydrography shapefile on the HYDROID attribute. A face may be part of multiple area water features. An area water feature may consist of multiple faces.
Edges Table Structure
The Edges table structure presented below. Fields with ** are not part of the TIGER structure and are unique to the DMD structure. The TIGER Editor can be used to derive the original TIGER data/records from this DMD version.
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