Digital

Digital Elevation Models The most basic and interesting geographical data type is the digital elevation model (DEM).

DigitalGlobe. (Corporate Profile). Corporate description DigitalGlobe is an imagery and information company building a constellation of high-resolution Earth imaging satellites and a comprehensive geo-information product store.

Digital elevation models may be prepared in a number of ways, but they are frequently obtained by remote sensing rather than direct survey.

Digital InterPlot Technical Requirements Plot server Windows NT 4.0 Service Pack 4 or greater, Windows 2000 Server Service Pack 3 or greater or Windows Server 2003 Microsoft Data Access Component (MDAC) 2.5 or greater.

Digital Aerial Photography The National Air Photo Library has introduced digital aerial photography on CD-ROM.

Digital Orthophoto Mosaic The mosaic below covers part of Jasper National Park in Alberta, Canada.

Digital data from the Canadian Geographical Names Data Base In the Canadian Geographical Names Data Base (CGNDB) at Natural Resources Canada, we store names records for populated places and physical features across Canada.

Digital data formats Currently, all data available for download are available in Shapefiles. Translation of data to other digital or hardcopy format is the sole responsibility of the downloader of the data.

Digital Orthophotography - A photo-quality digital image of surface features in their geometrically corrected, true map projection. The orthorectification process ties each pixel in a digital image to its true earth location.

Digital generalisation can been defined as "the process of deriving, from a data source, a symbolically or digitally-encoded cartographic data set through the application of spatial and attribute transformations".

Digital Image Processing To be effective in management decisions, a geographic information system requires timely, accurate update of many of its spatial data elements.

Digital Elevation Models (DEMs) and Viewing Modes In recent years, contour values have been digitized allowing them to be manipulated into versatile displays of topographic data as digital elevation models or DEMs.

Digital Data In a most generalized way, a digital image is an array of numbers depicting spatial distribution of a certain field parameters (such as reflectivity of EM radiation, emissivity, temperature or some geophysical or topographical elevation.

DIGITAL LEVELS 7-3. The level has been advanced, along with other survey equipment, into using electronic measurements.

Digital preservation differs from traditional archiving. Archives traditionally preserve physical objects (e.g. paper, photographs, microfilm) which carry information.

Digital orthophotos require several types of inputs to produce an orthogonally rectified image from the original perspective image captured by the sensor. These inputs are the following: 1) the unrectified raster image scanned from the diapositive or ...

Digital Photogrammetry Detailed discussion of all issues related to the practical use of digital photogrammetry.

Digital Vision/Getty Images The Sahara Desert is located in the northern portion of Africa and covers over 3,500,000 square miles (9,000,000 sq km) or roughly 10% of the continent (image).

Digital geoscience maps (WMS capabilities) The Geological Survey of Canada has published about 400 maps digitally.

Digital Map Publishing, Geospatial Solutions, March 1, 2005. Likened to Adobe Acrobat for GIS, ESRI ArcGIS Publisher creates digital map files that can be shared using ArcReader with a wide range of users, including those who do not have or use GIS.

DIGITAL ELEVATION MODELS (DEMs) A DEM is an image that contains topographic information. These are available for free download (at a low 1 km resolution), or at higher resolutions for a cost.

Digital Elevation Model (DEM): A digital representation of a continuous variable over a two-dimensional surface by a regular array of z values referenced to a common datum. Digital elevation models are typically used to represent terrain relief.

Digital Elevation Models Opening a Landsat Triplicate in Multispec Sources of Geographic Images ...

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.

Digital Geographic Information Exchange Standard DILI Digital Index of Land Information ...

Digital Raster Graphic Index (1:24K) (USGS, CDFG) srp_drg24.zip (138 kb) Preview Metadata ...

digital See Also : analog [mathematics] Represented in discrete, quantified units rather than continuously. Computers process and store information in digital form.

Digital: The ability to represent data in discrete, quantized units or digits. Digitizer: ...

digital map library A series of directories and subdirectories designed to uniformly organize a collection of spatial data. Map libraries organize geographic data spatially as a set of tiles and thematically as a set of layers.

Digital orthophoto quads are computer-readable air photos that have been processed to minimize distortions found on traditional photos.

Digital Navigational Chart (DNC) certified The DNC is a database of electronic charts created by NGA and its predecessors over the last 15 years.

Digital Chart of the World (DCW) - A digital cartographic database of the World, developed by the US Defense Mapping Agency (DMA, which is now part of National Imagery and Mapping Agency (NIMA)), with the cooperation of Australia, ...

Digital elevation model, map (image), and vector data Raster data type consists of rows and columns of cells, with each cell storing a single value. Raster data can be images (raster images) with each pixel (or cell) containing a color value.

Digital Data: Any data in computer readable format usually stored on magnetic tape, CD, disk or hard drive.

Digital Elevation Model (DEM) - The digital cartographic representation of the surface of the earth or a subsurface feature through a series of three-dimensional coordinate values.

Digital to Analog (converter) DAAC Div. des archives audiovisuelles et cartographiques, Archives nationales du Canada; Distributed Active Archive Center ...

*** Digital Data: Data representing distinct objects or digits that stand for some phenomenon in the real world. Data represented digitally may be manipulated to produce a calculation, sort, computation, or query.

DEM Digital Elevation Model. Diapositive (Diap) A positive photograph image on a transparent medium that is used in stereoplotting instruments.

The digital representation and manipulation of geographic concepts raise a number of fundamental research issues, many of which, though long-standing in traditional disciplines, have been re-energized by the development of GIS.

DEM- Digital Elevation Model. A GIS raster layer representing elevation. This is a common GIS product created at a variety of scales.

Even after digital computers became generally available, results were far from uniform. Many algorithms for Schwarz-Christoffel mapping suffered from low efficiency, limited precision, or instability, i.e.

Figure 3a. Digital revision of 1:100,000-scale digital line graph data to produce a 1:500,000-scale New Jersey State base map. Paneling and generalization are shown in three stages from 1:100,000 scale to 1:250,000 scale to 1:500,000 scale.

DLG stands for digital line graph, a form of digital map developed by the United States Geological Survey. DLGs supply users with the digital version of information printed on USGS topographical quadrangle maps.

Digital Exchange Format (DXF) ASCII text files defined by Autodesk, Inc. Originally used in CAD, now showing up in a third party GIS software.

[LINK] [LINK] A GIS can also convert existing digital information, which may not yet be in map form, into forms it can recognize and use.

41 a framework for recording spot elevations in a regular rectangular grid (matrix); an acronym originally created from Digital Elevation Model at US Geological Survey.

Not to be confused with satellite remote sensing which produces digital images, aerial photography provides black and white, color and infrared photographs on film.

In our case a clearinghouse is a decentralized system of servers located on the Internet which contain field-level descriptions of available digital spatial data.

Geocoding The conversion of features found on an analog map into a computer-digital form. In this process, the spatial location of the various features is referenced geographically to a coordinate system used in the computer's software system.

Operations that are required to encode data in a computer readable digital form (e.g., digitizing, scanning). See also data input. data conversion.

map digitization Conversion of map data from graphic to digital form. map, engineering Map showing information that is essential for planning an engineering project or development and for estimating its cost.

Colour management is a major concern in the distribution of digital imagery, on the Internet and in the graphic arts industry, right up to and including the printing stage.

Actually, it is a complex technology beginning with the digital representation of landscapes ca ptured by cameras, digitizers, or scanners, in some cases transmitted by satellite, and, with the help of computer systems, stored, checked, manipulated, ...

Often because GIS data is in digital form and can be represented with a high precision it is considered to be totally accurate. In reality, a buffer exists around each feature which represents the actual positional location of the feature.

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.

Spatial Database Catalogs and Libraries provide users an interface to search and download the digital maps, but do not match the need for interactive mapping or other GIS functions.

Before geographic data can be used in a GIS, the data must be converted into a suitable digital format. The process of converting data from paper maps into computer files is called digitizing.

Cannot be used to digitize data from analog maps to make them into digital forms which ArcView can use. Does not alter original Arc/Info coverages. Cannot perform Arc/Info commands (without programming in a scripting language).

Your results can be displayed as a digital map, printed as a paper map, combined with spreadsheet-like tables or charts, or displayed as such.

Maps, whether analog or digital, and spatial data, whether in vector or raster format, are related to some location. We mostly refer to these locations using coordinate systems.

See also: Information, Image, GIS, Map, Model