Proceed to GeoCommunity Home Page


SpatialNewsGIS Data DepotGeoImaging ChannelGIS and MappingSoftwareGIS JobsGeoBids-RFPsGeoCommunity MarketplaceGIS Event Listings
HomeLoginAccountsAboutContactAdvertiseSearchFAQsForumsCartFree Newsletter

Sponsored by:


TOPICS
Download Data

Accounts

USGS DRGs

USGS DEMs

USGS DOQQs

FEMA Flood Data

VMAP

NWI

Gazetteer

Census/TIGER

Index Grids

About Data

Contact


SpatialNews Daily Newswire!
Subscribe now!

Latest Industry Headlines
USGS Webinar: Using The National Map Services to Enable your Web and Mobile Mapping Efforts
Spectra Precisionís New MobileMapper 20 Handheld Extends GIS Capabilities in the Field
ZEB1 Hand Held Laser Scanner on US Tour
Boeing Adds to Analytic Software Line with 3 New Products
Chicago Projection Mapping Announces Summer 2014 Mapping Displays

Latest GeoBids-RFPs
Surveying Services*Germany
Data Logging Tags-MA
Aerial Imagery
Military Geospatial Support-VA
Geodata Mapping*Canada

Recent Job Opportunities
Cartographers/GIS Mapping Technician

Recent Discussions
GIS user groups in and near Connecticut
ArcGIS-How to get DMS display for a point layer
Georeference and shape file feature extraction
Beginner looking for step 1
Faulty 24k DRG ZIP file
Data HelpDesk - GIS Glossary


D
Back to Index

Datum
1) Point, line or surface used as a reference for a measurement of another quantity. Point, line, or surface used as a reference (i.e., surveying, mapping, or geology).
2) Combination of parameters and control points used to accurately define the three dimensional shape of the Earth (spheroid). For example, the North American Datum for 1983 (NAD83) is the basis for map projections and coordinates within the United States and throughout North America.

Digital Elevation Model
Digital cartographic representation of a terrain surface or a subsurface feature as defined by a series of three-dimensional coordinate values. A digital representation of a continuous variable over a two dimensional surface by a regular array of Z values referenced to a common datum.

DIME File
Acronym for Dual Independent Map Encoding, a data format used by the U.S. Census Bureau to encode street network and related data for the 1980 Census. See TIGER for details.

DTM
Acronym for Digital Terrain Model, a representation of terrain relief in a computer readable format. Also referred to as a Digital Elevation Model.

DXF
Acronym for Data Exchange Format, a standard spatial data exchange format for CAD systems. DXF files contain ASCII or binary (DXB) records each of which describes a vector complete enough so that it can be converted into a spatial feature by any spatial database management product able to process these files.


Sponsored by:

For information
regarding
advertising rates
Click Here!

Copyright© 1995-2014 MindSites Group / Privacy Policy

GeoCommunity™, Wireless Developer Network™, GIS Data Depot®, and Spatial News™
including all logos and other service marks
are registered trademarks and trade communities of
MindSites Group