Literally, meta is defined as a change or transformation. Data is described as the factual information used as a basis for reasoning. In terms of geographic information systems, metadata does not only include the data and attributes, but also describes how the geospatial and attribute data was collected and processed into its final form. Technical information pertains to what the allowable data in the entry can be and interpritative that describes the dataset. For programmers metadata is primarily a data dictionary, which describes the entities and attributes.
Programmers are interested in metadata as a data set and the data formats of the values.
The programmer also looks at the structure of the dataset, how the columns are organized, how many columns and rows in the table. In addition, software engineers and librarians use metadata to create effective interfaces and search strategies, for improving information retrieval. Such fields include indexing theme keywords, words such as aerial photography or trasportation that can be searched to find data relevant to such themes. For geographers, geologists, users of geographic information systems, metadata tells about data , attributes to these data and the quality of the data in the system. Descriptive information, data and attributes are 3 main classes of components captured by metadata.