关键词: 元数据, 地学元数据, 元数据分类, 元数据管理, 数据共享

Abstract: Metadata is an important concept in the field of database management, and the metadata ofearth science data which is called geo-metadata is valuable for earth-scientists to use and exploreearth science data. metadata is not a new concept, but the application of metadata of earth sciencedata is extended only by the utility of computer technology and the development of geographical information system (GIS). Geo-metadata are used to prompt management and utility of earth sciencedatabase which is different from ordinary database because of its spatial characteristics. Up to now,an universally accepted definition of metadata have not been created yet, but general views about theutility, contents, characteristics, function of metadata have been universally accepted. Metadata is a concept which has relations with Data dictionary, Data Encyclopedia, Data Repository, meta-Database, and metadata information management system through which metadata can be manipulated and managed. The classification system of metadata varies due to contents, utility field, andfunction of metadata. The general methods for metadata collection are key-in (through computerkeyboard), look-up tables (relates), inferring (from existing metadata or primary data), measurement (by some experiments), and computation (by existing data items). The function of geo-meatdata includes: (1) to help earth science data users to get specified data easier, (2) to control dataquality, (3) to convert data formats and transform data between different projection system, and(4) to descend the cost of earth science data management. Being at its infant stage, the development of GIS and data industry is eagerly necessary in China, so the study on the standards and thenormalization of earth science data and its metadata is urgent. At the end of the paper, the authorlists the purposes for the construction of geo-metadata in China.

Key words: metadata, geo-metadta, metadata classification, metadata management, data sharing