What is the significance of metadata in GIS and remote sensing?

Answer 1

Metadata is best defined as "Information about data". It helps users determine the usefulness and accuracy of data.

Without metadata, knowledge about our data can deteriorate rapidly. Let's look at an example:

1. A county GIS technician is tasked with overwriting a publicly available roads layer every month. Metadata could include:
2. Who updated the layer
3. When the layer was updated - alternatively, which point in time older versions represent
4. The estimated spatial accuracy
5. Values for coded attributes

This information could help users to contact the original author, ensure they're using the most updated version, protect the publisher from liability, and help a user when they don't know what the different codes in an attribute could mean (such as road classification).

Other examples of metadata are:

1. What project(s) a piece of data has been used for
2. The coordinate system for images and features
3. What transformations have been applied
4. Keeping examples of standard work

From the Federal Geographic Data Committee, metadata performs the following functions:

1. Define – document data requirements, standards, and workflows
2. Inventory/Evaluate – locate available data and determine fitness for use
3. Obtain – determine options and best method to access available data
4. Access –publish info about data and make it available to the user community
5. Maintain –assess data currency, relevance, and need for updates
6. Use/Evaluate – monitor fitness of the data to meet current mission/project needs
7. Archive – document the data schema for future use and determine components and formats to preserve

Metadata does not take long to create, and can save you and your organization in the long run. I've seen it as a consultant - the new users have no idea what data is used where, how recently it's been updated, or what its potential is.