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Document containing information about a series of datasets. A Data Dictionary is a form of metadata or “data about the data.” Information found in a data dictionary typically are names of the data, information about the attributes, and information about any relational tables to the spatial datasets.
Refers to the consistency and accuracy of data that is stored in a database.
The practice of searching through datasets to find patterns and trends. See: Spatial Data Mining.
Set of data that is stored in a given file.
Database Management System (DBMS)
System providing for the input, storage and retrieval of data.
A datum is a mathematical surface on which a mapping and coordinate system is based.
Digital elevation model (DEM)
A topographic surface arranged in a data file as a set of regularly spaced x, y, z coordinates where z represents elevation.
Digital Line Graph (DLG)
The digital format standards published by USGS for exchange of cartographic data files and for which Digital Line Graph data sets are delivered by USGS. Digital Line Graph files from the U.S. Geological Survey. These files include digital information from the USGS map base categories, such as transportation, hydrography, contours and public land survey boundaries.
Method of converting information from one format to another using a trace methology. Traditionally, digitizing has meant the creation of a spatial dataset from a hardcopy source such as a paper map or a plan. On-screen digitizing is the creation of a spatial dataset by tracing over features displayed on a computer monitor with a mouse. In both cases, the newly created dataset picks up the spatial reference of the source document.
The process of applying another data set over a shaded relief image.
Drawing Exchange Format (DXF)
An exchange format for CAD files. A format for storing vector data in ASCII or binary files; used by AutoCAD and other CAD software and convertible to ARC/INFO coverages.
DEM – Digital Elevation Model
DO(Q)Q – Digital Ortho(quarter)quads
DRG – Digital Raster Graphic
DSS – Decision Support System
DTM – Digital Terrain Model
More geographic concepts from the GIS dictionary:
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