Presentation on theme: "Metadata Lecture 7 October 5, 2006. Value of Documents Two very similar paintings of circus performers by Picasso from 1904 are put on the auction block;"— Presentation transcript:
Value of Documents Two very similar paintings of circus performers by Picasso from 1904 are put on the auction block; one brings tens of millions of dollars, the other hundreds of thousands. What is the difference? In one case, the ownership of the painting can be traced through sales slips and auction house records back to the estate of Picasso's dealer. The other painting appeared suddenly on the art market. They both appear to be original Picasso's but one lacks documentation. How can one be sure the undocumented painting is authentic?
What is metadata Meta is defined as a change or transformation. Data is described as the factual information used as a basis for reasoning. Put these two definitions together and metadata would literally mean "factual information used as a basis for reasoning which describes a change or transformation." In GIS, Metadata is data about the data. It consists of information that describes spatial data and is used to provide documentation for data products. Metadata is the who, what, when, where, why, and how about every facet of the spatial data.Metadata According to the Federal Geographic Data Committee (FGDC), metadata is data about the content, quality, condition, and other characteristics of data.
Metadata: A part of Geographic Data Metadata Metadata is the third component of geographic data. Geospatial data tells you where it is and attribute data tells you what it is. Metadata describes both geospatial and attribute data.
Why use and create metadata To help organize and maintain an organization's spatial data - Employees may come and go but metadata can catalogue the changes and updates made to each spatial data set and how each employee implemented them To provide information to other organizations and clearinghouses to facilitate data sharing and transfer - It makes sense to share existing data sets rather than producing new ones if they are already available To document the history of a spatial data set - Metadata documents what changes have been made to each data set, such as changes in geographic projection, adding or deleting attributes, editing line intersections, or changing file formats. All of these could have an effect on data quality.
Metadata Should Include Data about Date of data collected. Date of coverage generated. Bounding coordinates. Processing steps. Software used RMSE, etc. From where original data came. Who did processing. Projection coordinate System Datum Units Spatial scale Attribute definitions Who to contact for more information See an example of non-standard metadata (see)see
Federal Geographic Data Committee’s (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM) The FGDC is developing the National Spatial Data Infrastructure (NSDI) in cooperation with organizations from State, local and tribal governments, the academic community, and the private sector. The NSDI encompasses policies, standards, and procedures for organizations to cooperatively produce and share geographic data. The objectives of the CSDGM are to provide a common set of terminology and definitions for the documentation of digital geospatial data.
Metadata tools Metadata editors: - tkme / USGS - ArcCatalog / ESRI - SMMS / Intergraph - FGDCMETA / Illinois State Geological Survey - xtme / USGS Metadata utilities (check compliance and export to text, HTML,XML, or SGML): - mp / USGS - MP batch / Intergraph - ArcCatalog powered by mp/ ESRI Metadata Server - Isite / FGDC - GeoConnect Geodata Management Server / Intergraph - ArcIMS Metadata Server / ESRI mp: Metadata Parser
FGDC Clearinghouse the FGDC developed a clearinghouse that allows geospatial data creators to share their data however, the FGDC Clearinghouse is not a data repository. The data contained within the clearinghouse is actually stored on computer servers maintained by individual contributors. This allows contributors to manage their own data.
Two Components The FGDC Clearinghouse consists of 6 gateways and 250 nodes A gateway is a point of entry into the FGDC Clearinghouse A clearinghouse node is a database that contains metadata records. Individual contributors maintain nodes Besides the FGDC Clearinghouse, there are a variety of other communities that use FGDC-compliant metadata as the basis of their data sharing services. These so-called clearinghouse communities are often developed because the participating organizations have data of similar or complementary types. http://clearinghouse1.fgdc.gov/
Example of Using the FGDC Clearinghouse Your company is bidding on a spatial analysis project in the Chicago area. Your role on the proposal team is to find available data for the different components of the GIS you would be required to build. Of utmost importance is transportation data, and there is no way that your company will win the bid if they have to go out and collect new data. The data needs to be at least as current as 1995. Being a resourceful employee, you decide to explore the FGDC Clearinghouse to see what data is available. Source: www.esri.com http://clearinghouse1.fgdc.gov/ http://www.fgdc.gov/