Metadata or "data about data" describe the content,
quality, condition, and other characteristics of data. Metadata are used
to organize and maintain investments in data, to provide information to
data catalogs and clearinghouses, and to aid data transfers. Metadata standard
and are using automated indexing and serving mechanisms to provide access
to their holdings through the Internet.
Metadata is comprised with these following information:
A map legend is pure metadata. The legend contains
information about the publisher of the map, the publication date, the type
of map, a description of the map, spatial references, the map's scale and
its accuracy, among many other things. Metadata are simply that type of
descriptive information applied to a digital geospatial file.
Data Quality Information
Spatial Data Organization Information
Spatial Reference Information
Entity and Attribute Information
Metadata Reference Information
Twenty-five years ago, humans landed on the Moon.
Data from that era are still being used today, and it is reasonable to
assume that today's geospatial data could still be used in the year 2020
and beyond to study climate change, ecosystems, and other natural processes.
Metadata standards will increase the value of such data by facilitating
data sharing through time and space.
Example Minimum Metadata
Clearing House Technology and Model
Using the data elements defined in the Content
Standards for Digital Geospatial Metadata, governmental, non-profit, and
commercial participants worldwide can make their collections of spatial
information searchable and accessible on the Internet.
A fundamental goal of Clearinghouse is to provide
access to digital spatial data through metadata. The Clearinghouse
functions as a detailed catalog service with support for links to spatial
data and browse graphics.
Clearing House Model
Example Clearing House
PC Cluster: 2 PC Compute Node and 1 PC File Server are connected via
fast ethernet card, each of them runs 2 parallel ethernet card.
Load Balancing: DQS
File Server: CODA