Human Health Risk Assessment Data Dictionary (ORNL).Data Dictionary for Organic Carbon Sorption and Decomposition in Selected Global Soils (ORNL).MODIS Level 1B Products Data Dictionary (NASA).National Hydrography Dataset Data Dictionary.(Example only - updated NED Data Dictionary will be available soon) National Elevation Dataset (NED) Data Dictionary.Aerial Photo Single Frames Data Dictionary.Geological Survey Open-File Report 03-001: Data Dictionary EarthExplorer USGS Landsat Data Dictionary.Lastly, if there is a common, vetted, and documented data resource, it is not necessary to produce separate documentation for each implementation.Įxamples of Shared USGS Data Dictionaries Data dictionaries also provide information needed by those who build systems and applications that support the data. Shared dictionaries ensure that the meaning, relevance, and quality of data elements are the same for all users. Decision Making - assist in planning data collection, project development, and other collaborative effortsįor groups of people working with similar data, having a shared data dictionary facilitates standardization by documenting common data structures and providing the precise vocabulary needed for discussing specific data elements.Data Integration - clear definitions of data elements provide the contextual understanding needed when deciding how to map one data system to another, or whether to subset, merge, stack, or transform data for a specific use.Systems Analysis - enable analysts to understand overall system design and data flow, and to find where data interact with various processes or components.Application Design - help application developers create forms and reports with proper data types and controls, and ensure that navigation is consistent with data relationships.Communication - equip users with a common vocabulary and definitions for shared data, data standards, data flow and exchange, and help developers gage impacts of schema changes.Documentation - provide data structure details for users, developers, and other stakeholders.Business rules, such as for validation of a schema or data quality.Missing data and quality-indicator codes.Reference data (classification and descriptive domains).Entity-relationship (ER) and other system-level diagrams.Detailed properties of data elements (data type, size, nullability, optionality, indexes).A listing of data objects (names and definitions).Data dictionary contents can vary but typically include some or all of the following: A useful introduction to data dictionaries is provided in this video. Data dictionaries store and communicate metadata about data in a database, a system, or data used by applications.
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