Metadata or "data about data" describe the content, quality, condition, and other characteristics of data. The Federal Geographic Data Committee (http://www.fgdc.gov/) approved the Content Standard for Digital Geospatial Metadata (FGDC STD 001 1998) in June 1998. Visit the FGDC Clearinghouse (http://www.fgdc.gov/clearinghouse/clearinghouse.html) to learn more about how metadata is used in Internet based clearinghouses to search for specific data sets. 1
In the following lesson you will learn what metadata is and about the federal standard created by FGDC that governs the creation of metadata for GIS information. You will learn what information is included in metadata and what computer tools are available for creating metadata. 2
Metadata gives the GIS data user information about the data. Based on this information the user can make decisions about appropriate use of the data. Is the data suitable for my project? Maybe the scale is smaller than what you hoped or it s not as current as you would have liked, but you can make an intelligent, informed decision about whether to use it anyway, or to invest the additional time and money into developing a more appropriate dataset. 3
The FGDC metadata standard for GIS data was developed to give GIS users and producers a common terminology and format for metadata information exchange. GIS data that is published on internet is required to have FGDC compatible metadata (since 1995). Older GIS data may not be accompanied by metadata according to current standards. 4
Define appropriate use of data: GIS data of different scales should not be mixed and matched. For example a Fine Scale Parcel Map (1 = 200 ) should not be displayed with a Broad Scale State Highway Map (1 = 22 miles). It is inappropriate to put roads from the state highway map on your parcel data since broad scale data has a much larger allowable spatial error associated with the data. Many GIS projects span over large geographic areas. Cooperation and data exchange between agencies and organizations i is easier if we have a common language and a common standard. The bottom line is that data without metadata is not likely to be correctly used, and maybe not used at all! 5
The FGDC standard contains many components. However, the standard is broken down into mandatory and optional elements. 6
There are SEVEN metadata components in the FGDC metadata standard. Please review these components in the slide. Notice that only the Identification information and the Metadata reference information are mandatory entries. 7
How should I site the data? What is the name of the data set? Who developed the data set? What geographic area does it cover? What themes of information does it include? How current are the data? Are there restrictions on using the data? 8
The citation information is an important aspect of Component #1 in the FGDC standard. Use the information under the Citation section in the metadata when you reference GIS data in a report, thesis, dissertation or other document. This slide gives you an example how the citation information in the metadata can be condensed for the reference section in your document. Always reference the GIS data you use! 9
How good are the data? Is information available that allows a user to decide if the data are suitable for his or her purpose? What is the positional and attribute accuracy? Are the data complete? Were the consistency of the data verified? What data were used to create the data set, and what processes were applied to these sources? 10
Component #3 (Data Organization) explains what data type the GIS data layer is. For example point, line, polygon or raster data. 11
Component #4 describes the spatial reference information for the data, i.e. map projection and datum. Are coordinate locations encoded using longitude and latitude? Is a map projection or grid system, such as the State Plane Coordinate System, used? What horizontal and vertical datums are used? What parameters should be used to convert the data to another coordinate system? 12
Component #5 contains information about the attributes in the GIS layer. What geographic information is included? How is this information encoded? What do the column headings in the attribute table mean? What are the units? Were codes used? What do the codes mean? 13
From whom can I obtain the data? What forms are available? What media are available? Are the data available online? What is the price of the data? 14
Where were the metadata compiled? By whom? 15
In summary, there are a total of 32 mandatory elements in the FGDC standard, however only 4 items requires typing. Many elements are automated and some have pick lists. 16
This metadata tool is part of ArcCatalog. Notice the seven metadata components on the top bar in the tool. You can type directly in the ArcCatalog metadata tool to add metadata to GIS layers. It is highly recommended that you create metadata for GIS data layers that you or your organization have created. GIS data with no metadata will likely never be used by anybody since it is very difficult to assess the appropriate use of the data. Metadata is required for all data that is served on the Internet. 17
Additional metadata web sites if you are interested! 18
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