Digital Data Working Group
HTML Created: Jan 98
Published by the Resources Inventory Committee ...
Digital Data - A form of representation in which distinct objects, or digits, are used to stand for something in the real world--temperature or time--so that counting and other operations can be performed precisely.
Digital Data: Any data in computer readable format usually stored on magnetic tape, CD, disk or hard drive.
Digital data already in tabular form integrate into the GIS database in two very important ways. First, they form the basis for GIS feature attributes. In this case they must be linked somehow to the objects forming the spatial geometry.
Digital databases utilized in GIS mapping avoid these problems because they appear independent of scale and can easily be zoomed to depict very small areas or lines.
Map Audience ...
Digital databases used in the models included digital elevation model (DEM), digital line graph (DLG), vegetation (based on Soil Conservation Service DLG data), and landuse boundaries--based on Defense Mapping Agency data.
Digital data
much raster data is already in digital form, as images, etc.
however, resampling will likely be needed in order that pixels coincide in each layer ...
Digital Data Communication Message Protocol
DDE
DOE Data Explorer (US Dept. of Energy) ...
A digital database of geographic features, covering the entire United States and its territories, that provides a topological description of the geographic structure of these areas. The files are a public product created from the U.S.
The digital data and photographic images are used in a variety of time-critical applications over large areas. AVHRR data have been used by the U.S.
Since digital data are collected and stored in various ways, the two data sources may not be entirely compatible. So a GIS must be able to convert geographic data from one structure to another.
The amount of digital data that can be transferred over a computer network within a specified time period, usually measured in bits per second (bps).
A useful list of digital data sources can be found in Appendix 1.
3.6.3.1 A Note on the Integration of digital data sources ...
optical disk A digital data storage technology that uses optical media to store information. Optical disks are slower, but store more data and cost less per unit of stored data than magnetic disks.
Extraneous data must be edited, or removed from the digital data file.
86 Dual Independent Map Encoding, a digital database of streets and other census boundaries developed to conduct the 1970 US Decennial Census; an early and prominent implementation of a topological data structure. discount rate p.
Digital Data: Data represented in a computer compatible format.
Digital Geospatial Metadata - DGM: DGM was approved in June 1994 by the Federal Geographic Data Committee (FGDC).
data clearinghouse Source: ISO 19115 Collection of institutions providing digital data, which can be searched through a single interface using a common metadata standard.
Researchers have found that map-derived digital data in a GIS can improve the accuracy of interpretation of remotely sensed data while remotely sensed data provides the ability to update map products in a more expeditious manner.
The Nature of Satellite Digital Data
The starting point lies in the nature of the signal representing the remotely sensed scene. The MSS on Landsat is a good example from which to learn the principles.
Modern survey systems work with software specifically designed to process field data, perform computations, and produce a precise product, whether it be a GPS network, a digital database, or a computer-aided design (CAD) and drafting (CADD).
The DFIRM is comprised of all digital data required to create the hardcopy FIRM.
Another technical development in the 1980s was integration of video information with digital data in the computer by Steve Margle and Ed Tinnel at ORNL.
GIS are special-purpose digital databases in which a common spatial coordinate system is the primary means of reference. GIS contain subsystems for: 1) data input; 2) data storage, retrieval, and representation; 3) data management, transformation, ...
GIS technology and the availability of digital data on regional and global scales enable such analyses. The satellite sensor output used to generate the vegetation graphic is produced by the Advanced Very High Resolution Radiometer or AVHRR.
Commercial Mapping firms who sell maps and/or digital data take advantage of Geo Web Publisher to publish a geographic index depicting the maps and data on public Internet sites for potential customers and to publish samples of their products.
The life span of most digital data can range anywhere from 1 to 10 years. Commonly, digital data is valid for 5 to 10 years. The lengthy time span is due to the intensive task of data capture and input.
Translation of Existing Digital Data
Existing automated data may be available from existing tabular files maintained by outside sources.
It is digital data that cannot be displayed graphically as symbols or annotation on a map. This is usually attribute information, which accompanies maps in tabular form.
Digital data are more stable than paper media, easier to copy, and easier to distribute. Many web sites exist that distribute digital geospatial data.
The North Carolina Geographic Data Clearinghouse is part of a national effort to identify and share the rich digital data resources being produced by governments, universities, utilities, and many other organizations.
In addition, there is a rapidly growing wealth of digital data describing conditions that impact movement in the real world.
Satellite Imagery: Digital data obtained from sensors carried in satellites. It includes collecting data both in the visible and non-visible portions of the electromagnetic spectrum.
A format for transferring digital data between computer systems and software.
DLG (Digital Line Graph) - (1) A digital data format used by the USGS for large scale digital topographic maps. (2) A digital data file standard published by the USGS for exchanging digital cartographic data files.
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Hybrid systems also exist, for example the Navsys Advanced GPS Hybrid Simulator (AGHS), which records digital data from either real-world GPS field trials or MATLAB-generated signal simulation and plays them back either as an RF signal into GPS ...
Figure 7. Scanning paper maps to produce digital data files for input into a GIS.
Figure 8. Collecting latitude and longitude coordinates with a Global Positioning System (GPS) receiver.
digital formats A specific logical format in which digital data is maintained. This is often software specific.
digital map A map maintained in a computer readable electronic format.
It is one of four world map projections recommended for use with global, digital data by Steinwand, Hutchinson, and Snyder. Do you know what the other three are? Hint - one of them is actually the background on this page! ...
Can a property ownership map be related to a satellite image, a timely indicator of land uses? Yes, but, because digital data are collected and stored in various ways, the two data sources may not be entirely compatible.
Digital data captured through photogrammetric technique is used to generate cross-sections, contour overlays for photomaps, digital terrain models, volume calculations and conventional detail maps To offer these services, ...
DeMeter entitled 'DMA Digital Data Standardization' [14]. However for the wide community of GIS specialists it became apparent after the publication of the first version of the British data transfer standard (NTF) in 1986.
DNC data is stored in Vector Product Format (VPF) as an unclassified vector-based digital database containing significant features essential for safe marine navigation.
BY way of example, listed below is a contents summary for one of the more complex Australian Specifications. These are for both printed maps and digital data and the range of topics covered are a good indication of the issues which may need to be ...
In this manner, the Department will gradually obtain both the data and the skills necessary to use digital data for map printing and distribution to support GIS activities. Meanwhile, CMAC benefits from access to cleaned and labeled digital map data.
toward various of partial outcomes, such as the development of more user-friendly interfaces, network access to GIS, use of GIS as a communications medium, data creation based on local knowledge and sketchmap capacity, public access to digital data ...
data obtained from counties and cities was higher than the other statewide data sets. Since no single data set is complete, multiple data sets are used. Appendix C shows the counties in Washington for which we have acquired local level digital data ...
TRIM Terrain Resource Information Mapping: BC provincial digital data, available at scales of 1:20,000 and 1:250,000
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Undershoot A digitized line that does not quite reach a line that it should intersect.
 See also: Digital, Information, GIS, Geographic, Area
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