Abbreviations and Definitions
- AutoCAD, ACAD -
- A popular computer aided drafting program developed by AutoDesk. AutoCAD files typically have the extensions DWG and DXF.
- AVHRR - The Advanced Very High Resolution Radiometer
- is a broad-band, four or five channel (depending on the model) scanner, sensing in the visible, near-infrared, and thermal infrared portions of the electromagnetic spectrum.. MORE
- CAD - Computer Aided Drafting
- DEM - Digital Elevation Model
- This term is used both generally and specifically. In a generic sense it refers a grid of point elevation data. In a specific sense it refers to a format used by the U. S. Geological Survey for this data. Data is available for download from the USGS at a scale of. 1:250,000. Bruce Giddings publishes a catalog of Digital Elevation Data. It can be found at the beginning of each month on the newsgroup: comp.infosystems.gis. MORE
- DGN - Design File -
- A binary file format used by Intergraph's CAD program.
- DLG - Digital Line Graph
- A format used by the U. S. Geological Survey to prepare a digital vector version of a topographic map. DLGs at a scale of 1:2,000,000 and 1:100,000 can be downloaded from the USGS. MORE
- DMA - United States Defense Mapping Agency
- DOQ - A Digital Orthophoto Quad
- is a digital image of an aerial photograph in which displacements caused by the camera and the terrain have been removed. It combines the image characteristics of a photograph with the geometric qualities of a map. MORE
- DRG - A Digital Raster Graphic
- is a scanned image of a U.S. Geological Survey (USGS) standard series topographic map, including all map collar information. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator projection. The horizontal positional accuracy and datum of the DRG matches the accuracy and datum of the source map. The map is scanned at a minimum resolution of 250 dots per inch. MORE
- DWG - Drawing File -
- A binary file format used by AutoCAD.
- DXF - Drawing Exchange File -
- An ASCII file format developed by AutoDesk, the company that developed AutoCAD, to transfer drawing information to other drawing programs.
- EROS Data Center -
- Earth Resource Observation System Data Center The national archive run by the Department of the Interior's U.S. Geological Survey, to receive, process, and distribute data from United States Landsat satellite sensors and from airborne mapping cameras.
- GIS - Geographic Information System -
- A system for storing map data and attributes of map features in its geographic context.
- Interlaced -
- A procedure that displays an image in coarse form first, followed by finer detail. This allows you to get an idea about an image without having to display the entire image first.
- Lambert Conformal Conic -
- A map projection commonly used for areas that are longer in east-west extent than north-south extent.
- Landsat -
- Land Satellite - A series of satellites first launched in 1972 to study the resource of the land portions of the earth. There are two sets of satellites. The early systems were known as Multi-Spectral Scanners (MSS) add produced data from the early 1970s to the early 1990s. These satellites looked at 4 bands. An improved system known as the Thematic Mapper (TM) was introduced in the early 1980s and is a 7 band system.
- LULC - Land Use and Land Cover -
- The Land Use and Land Cover (LULC) data files describe the vegetation, water, natural surface, and cultural features on the land surface. The LULC mapping program is designed so that standard topographic maps of a scale of 1:250,000 can be used for compilation and organization of the land use and land cover data. In some cases, such as Hawaii, 1:100,000 scale maps are also used. Files at a scale of 1:250,000 and 1:100,000 are available for download from the USGS.MORE
- Raster Map Data -
- Map data that is a scanned image. Individual pixels represent an area on the portrayed map and not discrete points. The opposite is vector map data.
- SDTS - Spatial Data Transfer Standard -
- The latest format to be used by U.S. government agencies to transfer of spatial data between dissimilar computer systems. The SDTS specifies exchange constructs, addressing formats, structure, and content for spatially referenced vector and raster (including gridded) data. MORE
- SPOT -
- A high resolution satellite Earth Observation System designed by CNES (Centre National d'Etudes Spatiales), France, and developed with the participation of Sweden and Belgium. MORE
- TM - Thematic Mapper - Second generation Landsat satellite.
- Transparent -
- A property of an image that allows the background of the web page to show through the background of an image.
- Transverse Mercator -
- A map projection commonly used for areas longer in north-south extent than east-west extent.
- UTM - Universal Transverse Mercator -
- A commonly used map projection developed by the U.S. Army. It is based upon the Transverse Mercator projection.
- Vector Map Data -
- Map data that is composed of points, lines, and polygons that are described by a one or more points in XY or latitude-longitude coordinates with associated attributes. The opposite is raster map data.
Back to Smorgasbord of Internet Sites
 |
|
© 1999 John Sharry
jsharry@ix.netcom.com
Geology and Geophysical Interpretation
Project Management
Basin Studies
Computer application support and custom databases
Web Programming