What is metadata?
- Data that provides information about data.
- The term “Meta- “ means change and metadata describe the origins of and track the changes to data.
- Describes information resources.
- In a GIS, metadata provides additional information on both spatial and attribute data
- Metadata may be thought of as a “library catalog” that describes data in terms of author, citation, subject, keywords
- The catalog might include how accurate and recent the data is, restrictions associated with using and sharing the data, important processes in its life cycle such as generalizing features, etc.
Metadata provides additional information on
both spatial and attribute d
Metadata answers questions like:
- What does the dataset describe?
- Who produced the dataset?
- Why was the dataset created?
- How was the dataset created?
- When was the dataset created?
- How reliable is the data (scale?); what problems remain in the dataset?
- How can someone get a copy of the dataset?
Metadata is highly descriptive
Why have metadata ?
- File Systems are getting bigger
- Data sets are larger
- File counts have increased
- People forget/Record keeping
What are Advantages of Metadata?
▪ Enables data exchange
▪ Efficient use of (existing) resources
▪ Building productivity
▪ Enhancing data quality (data standards)
▪ Cost saving on business activities
▪ Reduce the redundancies\duplication
▪ Re-sell value
Development of Metadata
- Initially no agreement on how to document data sets
- Each person or agency documented data in a different way
- Consequence of this = Inefficiencies and duplication
- 1990’s USA - Federal Geographic Data Committee (FGDC) produced the Content Standard for Digital Geospatial
Metadata (CSDGM) bill on metadata. - 2003 - International Standards Organization (ISO) developed and approved ISO 19115– Geographic Information Metadata (https://www.iso.org/home.html)
- ISO 19115– also used in South Africa
7 Mandatory Elements of metadata:
- Dataset title
- Dataset reference date
- Dataset language
- Dataset topic category
- Abstract/Summary
- Point of contact
- Date Stamp
14 Conditional Elements of metadata:
- Responsible party
- Geographic location
- Spatial resolution
- Distribution format
- Reference system
3 types of metadata?
- Descriptive metadata
- Structural metadata
- Administrative metadata
What is descriptive metadata?
describes a rresource for purpose suc as discovery and identification.
It can include elemets such as title, abstract, author and keywords.
What is structural metadata?
metadata about containrs of metadata and indicates how compund objecs are out together, eg. how pages are ordered to from chapters.
What is administrative metadata?
imformation to help manage a resource such as when and how it was created, file type and other technical information and who can access it.
metadata content?
- The metadata of a shapefile are typically stored in the .xml extension
- A shapefile, its geometry (.shp), its properties and attributes (.dbf) will display whether the .xml extention is present or not (i.e. optional extension).
Elements of metadata
*Title
*Dataset abstract
*Responsible party
*Dataset theme
*Dataset extent
*Reference date
*Metadata date
*Resolution
*Scale, accuracy
*Reference system
Function of metadata:
Description, search
Description
Data access, sharing
Keyword search
Spatial search
Temporal search
Maintenance
