# Presentation: 277291

## GOVERNMENTAL UNITBOUNDARY DATA CONTENTSTANDARD

- Progress Report
- To the SCDD
- June 2002

## BACKGROUND

- The SCDD submitted a Proposal for a National Spatial Data Infrastructure Standards Project to the FGDC SWG in November 1997
- The Proposal was accepted and completed Public Review in April 1998
- A Progress report was made to SCDD in February 1999
- Currently a working draft (v. 2.1) is to be presented at the NACo and ESRI conferences in July 2002

## OBJECTIVE

- 	The purpose of the Governmental Unit Boundary Data Content Standard is to establish the content requirements for the collection and interchange of GU and legal entity boundary data, and to facilitate their maintenance, analysis and comparison of the information

## PROBLEMS IN COUNTY BOUNDARY FILES

- 	With the Standard, problems in boundary exchange should diminish, such as:
- No projection/Unknown projection
- Lack of Metadata
- Different File Formats
- Too many layers
- Digitizing error

## SCOPE

- 	The Standard identifies and defines the components required for describing the content of a GU or legal entity boundary and the data needed for boundary data exchange.

## GOVERNMENTAL UNIT (GU)

- 	The Standard adopts the FIPS 55-3 definition of a GU.  A GU is defined as,
- 	“a legally bounded geographic entity that has the ability to have elected or appointed officials and raise revenues through taxes.”

## LEGAL ENTITY

- 	The Standard adopts the FIPS 55-3 definition of a legal entity.  A legal entity is defined as,
-    “a geographic unit with legally defined boundaries established under Federal, State, or local law as a governmental unit or as an area for the administration of governmental function.”

- The Standard applies to both GUs and other legal entities.
- Although the Standard utilizes the FIPS definition, it may be used with other GUs and legal entities.

## FGDC-RECOGNIZED GOVERNMENTAL UNITS

- Nations
- States and equivalent entities
- Counties and equivalent entities
- Incorporated places, including consolidated cities
- County subdivisions

## FGDC-RECOGNIZEDGOVERNMENTAL UNITS (CONT.)

- American Indian reservations
- American Indian tribal subdivision
- Alaska Native village
- Alaska Native Regional Corporations
- Special district
- Barrio, Barrio-Pueblo and Subbario
- Hawaiian Home Land
- Minor Civil Division

## OTHER GUs AND LEGAL ENTITIES

- Congressional District
- State, local and tribal Legislative Districts
- Voting District/Polling District
- School District
- Federal, State, local or tribal owned and managed land
- Federally regulated area

## GU AND LEGAL ENTITY

- Information, Identification and Relationships

## INFORMATION

- 	Information about GUs and legal entities may be presented at two levels:
- Type Level – pertaining to categories of GUs or legal entities
- Instance Level – pertaining to single occurrences of a GU or legal entity

## IDENTIFICATION

- 	Identification is essential for the describing GU and legal entity boundaries
- Type Level – Example: type name, type definition
- Instance Level – Example: reference to the type level identifier, instance name

## RELATIONSHIPS

-  Three types of relevant relationships in describing GUs:
- Topologic
- Maintenance
- List

## Topologic Relationships

- Conditional or characteristic relationships that apply to GUs and legal entities
- Bounded
- Non-Bounded
- Composes
- Composed of

## Bounded

- A GU or legal entity contained within a contiguous delimiting line

- A

- State Park A is bounded

## Non-bounded

- A  GU or legal entity lacking a delimiting line

- A

- Entity A is non-bounded

## Composes

- A GU or legal entity that always forms a part of another feature object

- A

- B

- C

- 1

- Counties A, B and C compose State 1

## Composed of

- One or more topological or feature objects always are the ingredients of the GU or legal entity

- A

- B

- C

- County 1 is composed of Minor Civil Divisions A, B, and C

- 1

## Maintenance Relationships

- Provide some common areal information between one or more GUs or legal entities and geographic area features
- _Coextensive With_
- _Contains Nested_
- _Nests Within_

## Coextensive with

- A one-to-one areal maintenance relationship between two different governmental units

- Metropolitan Area A is coextensive with County B

- B

- A

## Contains Nested

**Contains Nested**

- A one-to-many areal maintenance relationship between different feature objects

- C

- B

- A

- County A contains nested school districts B and C

## Nests within

- A many-to-one areal maintenance relationship between different feature objects

- A

- B

- Voting District B nests within Congressional District A

## List Relationships

- 	Optional, separately maintained list of areal links between feature objects, maintained independently of the geographic and feature coverage within a database
- 	Only maintained at the type level, including a listing of all instances of a type

## BOUNDARY DESCRIPTION COMPONENT CHARACTERISTICS

- _Name_ – a label assigned to a component
- _Definition_ – a component description
- _Obligation_ – a descriptor indicating whether a GU Boundary Description Component shall be present (contain values)
- Mandatory
- Conditional
- Optional

## BOUNDARY DESCRIPTION COMPONENT CHARACTERISTICS

- _Condition_ – specifies when a condition is mandatory
- _Maximum Occurrences_ – the number of the instances a component may have
- _Data Type_ – Examples: text, integer, real or date
- _Domain Values_ – set of distinct values for each component

## Future Work on the Standard

- Presented at ESRI and NACo Conferences in July, 2002.  Comments will be accepted and adjudicated.
- Work on boundary file metadata and UML modeling must be completed.
- Upon the completion of the working draft, the Standard will be submitted to the SCDD for review and comments.
- Once these comments are incorporated, the draft will be given to the FGDC Standards Working Group and, once approved, to the Coordination Group to be approved and sent out for public review.

## Contact Information

- April Avnayim
-  april.l.avnayim@census.gov
- Anne Ruth
-  anne.ruth@census.gov