NOTE: The NCGDC is written using frames. This html based format allows a user to maintain the contents of one window, while changing the contents of another window being shown on the same screen. Not all web browsers support frames. The NCGDC will still work with non-frame supporting browsers, it will just appear differently. (Remember to use the "back" button to return to this page).

Let's look at the NCGDC Homepage. (Select on the link below, look at the pages components and layout, then use the "back" button to return here.)

North Carolina Geographic Data Clearinghouse

Search Types - The NCGDC is set up to enable 4 types of searches:

1.) Participant List Search - this enables a user to select from a listing of agency names and see the data layers they have available.

(Select on the link below, then select the "Participants" box in the Virtual Index, then use the "back" button to return here).
NCGDC Participant List Search.

2.) Subject Index Search - this is like a card catalog of themes and subthemes. This list is used to determine how the data is organized by subject. By selecting on a theme or subtheme from the subject index, the user is linked to the listing of data layers under that theme.

(Select on the link below, then select the "Subject Index" box in the Virtual Index, then select a theme or subtheme, then use the "back" button to return here).
NCGDC Subject Index Search.

3.) Data Themes Search - this enables a user to select directly on one of the 8 major themes, skipping the subject index.

(Select on the link below, then select the "Data Themes" box in the Virtual Index, then select a theme, then use the "back" button to return here).
NCGDC Themes Search

4.) Custom Queries Search - this enables database which have had their metadata indexed using the Isite software suite, to be searched using a form to input specific search parameters.

(Select on the link below, then select the "Custom Queries" box in the Virtual Index, then select "National Geospatial Data Clearinghouse", select "Connect to Service", look at the query parameters which can be used to pose a search against the North Carolina Geographic Data Clearinghouse or other databases, then use the "back" button to return here).
NCGDC Custom Queries Search.

Basic Clearinghouse Structure Graphic briefly shows the flow of the searches between the NCGDC and the metadata files which they access. Right now, since the NCGDC custom query is under construction, not all of the metadata files are accessible using the custom query search, while they all are available using subject index, themes and participant searches.

Appendix A has two examples of other Clearinghouse sites , one from the state of Oregon and the other is the Federal Geographic Data Committee's (FGDC) National Geospatial Data Clearinghouse.