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NHPN Description, Schema, and File Structures

The Node Attribute Table

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The Node Attribute Table contains single fixed length records for each node referenced by an arc end point. Each node is geographically located and contains the following attributes.

Table Name

sXXnhpn.nat[1]

Record Length

98

Record Type

Fixed Length

Reference Section

RECTYPE

Character

Always 'I'

VERSION

Numeric

Version Information

RECID

Numeric

Unique Node ID

Key Section

STFIPS

Numeric

State FIPS Code

CTFIPS

Numeric

County FIPS Code

LGURB

Numeric

Adjusted Urbanized Area

SMURB

Numeric

Adjusted Small Urban Area

Description Section

BNDRY

Numeric

Boundary Status

NAME

Character String

Node Name

Each column is described below:

RECTYPE

Data Type

Character

Width

1

Position

1 - 1

Domain

'N'

Description

Identifies Node File records

VERSION

Data Type

Integer

Width

2

Position

2 - 3

Domain

20 - 99

Description

The Version ID is used to maintain consistency across data files containing alternate releases of the NHPN. The Version Code consists of a leading Version Number and a trailing Revision Number, thus, 30 describes Major Release 3 Revision 0 and similarly 32 would describe Major Release 3 Revision 2.

RECID

Data Type

Integer

Width

10

Position

4 - 13

Domain

Positive Integers

Description

The RECID is a unique numeric ID associated with each node.

STFIPS

Date Type

Integer

Width

2

Position

14 - 15

Domain

00 - 99

Description

State FIPS code for the node. Nodes that are a State Boundary node will have a value of 99 for the STFIPS field.

CTFIPS

Date Type

Integer

Width

3

Position

16 - 18

Domain

000 - 999

Description

3 digit FIPS Code for the County the node is contained in. (County FIPS are identified uniquely within a given State using the three digit code and uniquely within the US by prefixing the two digit State FIPS code to create a 5 digit code). Nodes that are a County Boundary node will have a value of 999 for the CTFIPS field.

LGURB

Data Type

Integer

Width

3

Position

26 - 28

Domain

0 - 999

Description

Three digit HPMS Urbanized Area code for the Adjusted Urbanized Area in which the node lies. A value of 0 indicates the node is outside any HPMS Adjusted Urbanized Areas. Nodes that lie on the boundary of an Urbanized Area will have a LGURB value of zero.

SMURB

Data Type

Integer

Width

5

Position

29 - 33

Domain

0 - 99999

Description

5 digit CENSUS Adjusted Small Urban Area code for cities under 50,000 population in 1990. A value of 0 indicates the node is outside any Adjusted Small Urban Area. Nodes that lie on the boundary of a small urban area will have a SMURB value of zero.

BNDRY

Data Type

Integer

Width

2

Position

34 - 35

Domain

0 - 17

Description

The BNDRY Flag is used to identify nodes which lie on the boundary of logical polygons maintained within the NHPN.

0

Not a boundary node

1

County Boundary

2

Adjusted Urbanized Area

4

Adjusted Small Urban Area

10

State Border

Notes

The values for BNDRY are additive and can be used to describe a node which lies on the border of more than one boundary. For example a node at a State border will also be a county border node and will therefore, have a value of 1 + 10 = 11. Similarly a node which lies on the boundary of an Urbanized Area and a small urban area will have a BNDRY value of 4 + 2 = 6. If it were also a county boundary it would have a value of 1 + 2 + 4 = 7.

NAME

Data Type

Character String (left justified)

Width

30

Position

36 - 65

Domain

Alpha-Numeric character set (A - Z, 0 - 9)

Description

The NAME field can be any character string used to identify nodes such as the name of nearby towns, geographical features, interstate exits, intersection descriptions, etc. Names need not be unique and cannot contain punctuation characters other than hyphens, underlines, and blank spaces.

Updated: 04/05/2012
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