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ownership boundaries. Other thematic datasets are 
numerous and include information about land use, land 
cover, infrastructure for drinking water supplies, 
infrastructure for waste water treatment, environmental 
sensitivity zones, and regulatory boundaries. A majority 
of the data pertain to environmental conditions and 
natural resources. 
Several important features characterize all data that are 
supported in the Corporate Geographic Database. The 
GICC has prepared a document that contain desired 
characteristics of the database. Those desired 
characteristics are: 
* The data contents are consistent within each theme; 
* The data are reliable. In other words, the data meet 
data content and mapping standards, are 
maintained, contain metadata, and are considered to 
be official and certified; 
* The data are produced with the cooperation of the 
appropriate authorities; 
* The data are not redundant; 
The database is produced and maintained by many 
government and non-government organizations; 
* The data conform to National Spatial Data 
Infrastructure objectives of the FGDC and the GICC 
for Geospatial Data Standards (including metadata), 
the Geospatial Data Clearinghouse and the 
Geospatial Data Framework; 
* The database is centrally coordinated; 
* The data are "on-line," physically distributed, and 
accessible and supported through the North Carolina 
Information Highway; 
* Data determined to be "sensitive" will be appropriately 
protected from dissemination. 
It is important to recognize that the Corporate Geographic 
Database contains data that are largely developed and 
maintained by sources other than CGIA. For example, 30 
Statewide datasets are supported by agencies of the 
North Carolina Department of Environment and Natural 
Resources through Data Custodian Agreements. 
Data Custodians 
Most of the datasets included in the Corporate 
Geographic Database are dynamic and require frequent 
updates. Updates to the data are required at regular 
intervals (daily, weekly, monthly, quarterly, annually). 
Datasets of this nature require that an agency be 
designated as the authority for data maintenance. 
Agencies designated as the authority for maintenance 
are called data custodians. A data custodian agreement 
with CGIA is a formal declaration of the maintenance 
responsibility by each partner. Specific responsibilities, 
Such as the process and update frequency are written 
into these agreements. 
Data Custodians are an important component of the 
partnership program as they significantly contribute to 
the integrity of data collected, maintained, and 
distributed through the Corporate Geographic Database. 
Local Resources 
. Although initially supported by state and federal agencies 
at smaller mapping scales, framework data for the 
Corporate Geographic Database is evolving to data that 
largely originate in local government. Data generated by 
local organizations include thematic categories such as, 
digital imagery, roads and streets with street addresses, 
public and private ownership boundaries, land use, and 
infrastructure mapping of water and sewer lines. 
Geospatial data originating from local resources are 
derived from large scale maps and high resolution 
imagery. Map scales are 1:4,800 to 1:1,200 and image 
resolution (pixel size) is sub-meter. 
The data produced by local resources require vast 
storage capacities and are frequently updated to 
accommodate changes that occur. It is imperative that 
the data reside with the local resource on an as needed 
basis for the consumer and provided for universal access 
using high speed telecommunication technology. 
Several prototype arrangements are underway in North 
Carolina with local organizations to make this a reality. 
The development of metadata and a geospatial 
clearinghouse node is one approach to creating the 
technological infrastructure for local participation in the 
NSDI and the Corporate Geographic Database. 
Geospatial Data Clearinghouse 
The North Carolina Geographic Data Clearinghouse is an 
initiative developed to advance public access to 
geographic information resources. The Clearinghouse is 
a World Wide Web application that Internet "browsers" 
operating software like Netscape use to search listings of 
available geospatial datasets. The Clearinghouse 
enables a browser to conduct custom query searches of 
indexed documentation, or metadata, of databases 
through the use of a web form. The user is also able to 
search for geospatial data using either a subject or 
organizational listing. As a condition of being listed in the 
clearinghouse, all data offered in the Corporate 
Geographic Database require metadata that are fully 
compliant with the Federal Geographic Data Committee's 
Content Standard for Geospatial Metadata (FGDC, 1994), 
a federal and state standard. 
The Clearinghouse is designed to enable users to search 
across numerous agencies for geographic data without 
having to sift through other information the agencies 
serve at their Internet site. The locations of the 
geographic data listings are linked directly through the 
Clearinghouse. A user who begins a session at the 
Clearinghouse homepage will end up connected to the 
agency's page where the metadata, graphics, and data 
reside. 
Organizations serving data through the Clearinghouse 
are required to provide metadata in a format compliant 
with the Content Standards for Digital Geospatial 
Metadata at a minimum, but may also serve background 
information, reference maps, and dataset graphics. If the 
GIS data file is served, it is linked through the metadata. 
The state’s Clearinghouse was originally made possible 
when CGIA, on behalf of the GICC, was awarded a grant 
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 139