Cartesian Coordinate: Point whose location in space is expressed in terms of its distance above or below an X, a Y and a Z coordinate plane. Location of a point on a plane is expressed by two coordinate values, one representing the distance from the Y-axis and the other representing the distance from the X-axis.

Cartography: Science and art of making maps and charts. More broadly, the term includes all the steps necessary to produce a map: planning, aerial photography, drafting, editing, color separation, and multicolored printing. With regard to computerized spatial databases, a cartospatial feature is a point, line, arc string, chain, polygon, symbol, text or other form of spatial entity. Functionality of cartographic information systems is limited to encoding, displaying and measuring cartospatial features.

Cell: The basic element of spatial information in a grid data set. A group of cells form a grid. Cells store values that can be related to a table.

Centerline: Linear feature representing the midpoint along a linear element like a road or stream.

Centroid: Any point used to label the attribute information link in a spatial database (polygon, line or point). The geometric center of polygon may be calculated as the average location of all vertices of a polygon boundary. Any single location within a polygon, arithmetically derived or not, to which attribute information about that polygon is linked.

Character String: A consecutive sequence of alphanumeric characters (i.e. ABC, def, 123) used together as a single unit for purposes of display or analysis.

Clean: Process for identifying and correcting potential errors in digital map line work. For example, closed polygon areas made up of boundary segments wherein the location of the end point of one segment is identical with the start point of the next segment. In other words, line work is free of gaps and dangles.

Client/Server: Communications between computers. The client computer is typically a desktop microcomputer device using a software program to contact and obtain data from a server computer. The server is typically a minicomputer, workstation, or mainframe computer integrated over a network. However, the server can be a microcomputer linked to multiple storage devices.

COGO: Coordinate geometry. A method of data input and analysis similar in principle to metes-and-bounds surveying. Input begins at a point, moves at a given angle or in a certain direction for a set distance, and continues in the same fashion until a geographic feature is completely outlined.

Composite Mapping: Overlaying and combining data types from two or more map overlays to create a map displaying a combination of information from different thematic maps.

Conformal Projection: A projection wherein the scale is the same in every direction at any point. Meridians and parallels intersect at right angles; the shape of small areas and angles with very short sides are preserved. Most area values are distorted.

Conic Projection: A projection in which the surface is drawn as it would appear if projected on a cone wrapped around the Earth. A Lambert projection is a form of Conic projection often used for maps of the continental United States, France, and other countries.

Connectivity: A topological property relating to how geographical features are attached to one another functionally, spatially, or logically. In a water distribution system, connectivity would refer to the way pipes, valves, and reservoirs are attached, implying that water could be traced from its source in the network, from connection to connection, to any given final point. Functional, spatial and logical connectivity are examples of relationships that can be represented and analyzed in a GIS database.

Continuous Map: A means of storing a digital map as if it represented a continuous, unbroken surface. Many large GIS databases are broken into subfiles, which represent smaller sections of a larger area. These separate subfiles are referred to as tiles or facets. A continuous map allows the user to move in any and all directions without moving from file to file. Maintaining the illusion of a continuous map in a computer is a challenging problem because computers typically store data in strings, in linear order, on magnetic or optical storage media.

Contour Mapping: Display of contour lines, each of which represents a constant value, typically surface elevation, throughout its length.

Control Points: Exact positions of often-surveyed geographic features used to register map sheets and transform coordinates.

Conversion: The process of transferring data derived from existing records and maps to a digital database. Conversion is a major input problem and can consume the greatest share of time in a GIS project.

Cover: Environmental data overlay that defines the surface of the earth in terms of vegetation type in non-developed areas (i.e., forest, rowcrops, orchards, grasslands) and land use type in developed areas (i.e., residential, transportation, vacant, light industrial). Land cover map overlays can be derived from interpretation and classification of remotely sensed images.

CPU: Central Processing Unit. The portion of a computer that directs and supervises all of its functions (screen, printer, disks, etc.) and controls the interpretation and execution of instructions assigned by a program called the operating system.

Cylindrical Projection: Projection in which a surface is drawn as it would appear if projected on a cylinder wrapped around the Earth. Mercator projection is a form of cylindrical projection in which the surface is drawn as it would appear if projected on a cylinder wrapped around the Earth in a north-south direction.

D

Data: General term for information including facts, measurements, classification or value representations from which conclusions can be inferred. Things known about real-world entities; results of observations or measurements of such features.

A single datum has three potential components:

1. Attributes: attributes describing the substance characteristic variables, values, and similar qualities of the datum.
2. Geographic: information describing the position of the datum in space relative to other data.
3. Temporal: information describing the instant or period of time for which the datum is valid.

Database Design: Structure of a database. In spatial data management systems, refers to both the spatial and tabular parts. A collection of interrelated data sets stored together and controlled by a specific schema for efficient management of information. A consistent and specified set of procedures is used for building, maintaining, accessing, and interrogating information from a database.

Datum: A set of parameters and control points used to accurately define the three-dimensional shape of the Earth (e.g., as a spheroid). The datum is the basis for a planar coordinate system. For example, the North American Datum for 1983 (NAD83) is the datum for map projections and coordinates within the United States and throughout North America.

DBMS: Database Management System. A DBMS is a set of computer programs used for the information within a single project, or within one unit or the whole of an organization.

Default: An automatically designated value, setting, or an action automatically taken, unless otherwise specified. Values or parameter settings defined by the software vendor or the system user that are applied automatically during data entry, editing, and/or analysis operations unless changed by the user. For example, a default snap radius is set at 5 model units unless the current polygon processing transaction requires a different one to be applied. For data models there can be default symbol libraries, file and attribute naming conventions, DBMS configurations, interface links, and spatial database formatting schemes.

DEM: Digital Elevation Model. 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. The format of the USGS digital elevation data sets.

Demographic Data: Characteristics of human populations, such as size, growth, density, distribution, and vital statistics.

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

Digitize: The process of converting source materials, prepared manually, into the digital codes stored and processed by computers. Digitizing involves tracing map features into a computer using a digitizing tablet, graphics tablet, mouse or keyboard cursor.

DIME File: 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. Superseded by TIGER. (See TIGER)

Dissolve: Removing boundaries between adjacent polygons having the same value for a specific attribute. Combining polygons that would otherwise be assigned the same color or hatch pattern in a thematic map display. Process of aggregating neighboring polygons based on a matching value for some attribute.

DLG: 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.

Document: May be a textural report, spreadsheet, picture, or spatial database stored as a file in the computer. Typically, a document is a file containing ASCII text. It is a file created within an application, for example, a letter created in a word processor or a graph created in a spreadsheet or graphics program.

Double-Precision Accuracy: Refers to a high level of coordinate accuracy based on the possible number of significant digits that can be stored for each coordinate. Double-precision coverages store up to 15 significant digits per coordinate, retaining the accuracy of much less than one meter at a global extent. (See also Single-Precision Accuracy).

DOS: Disk Operating System developed for IBM by Microsoft Corporation that has become a standard Microcomputer operating system. A system program that allows transfer of programs and data back and forth from the computer processor and the disk drive.

DPI: Dots (or Pixels) Per Inch. A measure of the resolution of graphics displays.

Drawing File: Digital CAD equivalent of hard copy document. Some systems refer to them as designs or design files. A collection of graphical features stored as a set of spatial information in a computer.

DTM: Digital Terrain Model. A method of transferring elevation data into a contoured surface or a three-dimensional display.

DXF: Drawing Exchange Format. A file exchange format developed by Autodesk, Inc. for its AutoCAD drafting software. DXF files are ASCII records of all objects in a drawing file.

E

Easting: The east-west, X, coordinate in a rectangular coordinate system.

Edge Matching: An important part of the creation of a digital map or GIS database. One digital map may encompass many paper maps, but when the paper maps are laid edge-to-edge, features running across boundaries of the map sheets are not always properly aligned. These misalignments occur for many reasons including survey error, cartographic generalization, and problems of map projection and compilation. Edge matching is a term applied to a variety of techniques employed to resolve these inconsistencies, including warping and rubber sheeting.

Editing: Detection of errors in text records or spatial database features and the implementation of the needed correction. Corrections can include additions, deletions, and rearrangements, as well as changing size, font, style, color, orientation, alignment, scale, and rotation. Editing techniques exclusive to spatialfeatures include changing elevation, thickness, width, attribute assignments, surface textures, dimensioning and others.

Entity: Geographic feature that exists and is distinguishable in the real world. For example, a land parcel, road, building, manhole, or pole.

Ethernet: A local area network originally developed by Xerox DEC and Intel that interconnects personal computers via coaxial cable. A type of computer network established using coaxial cable, twisted pair cable or fiber optic cable. It has a network protocol defining the physical and data link layers of the Open Systems Interconnect (OSI) model.

F

Facility Management-In conjunction with Automated Mapping, the record keeping of information concerning spatially distributed assets or facilities. Typically used for asset accountability and maintenance management operations. There is no spatial component. If a spatial component is added so that records in a Facility Management system are linked to features in an Automated Mapping System, the combination is referred to as an AM/FM system.

Feature: Natural and man-made geographic features represented by points/symbols, lines, and areas on a map. Object in a geographic or spatial database with a distinct set of characteristics. A defined aspect of the earth's surface that is not further subdivided. For example, a road segment, manhole, building, or area designated having the same soil type.

Feature Locking: Method for preventing a second user from editing a feature while the original user is performing an edit. Locking prevents writing on a feature by others while a feature or record is currently "checked out" for modification. When a transaction is started, the selected feature, and in some cases the linked attribute record, is designated as locked in such a manner that no other user can write on the feature until it is released (the lock designation is removed).

Field: Columnar data item in a DBMS.

File: In computing, a collection or set of related digital data stored on a computer disk and accessed/ retrieved according to an assigned unique name. A collection of related computer records grouped under a common heading and containing data according to specific units.

Fill: Solid coloring covering an area bounded by linear or curvilinear segments. A solid color rendering of a polygon, sometime referred to as a "solid fill".

Fillet: An arc constructed between and tangent to two converging lines.

Filtering: Process of removing unwanted components from tabular or spatial data.

1. In vector spatial database, a variety of smoothing algorithms used to reduce file size by removing excessive turning points along a linear feature.
2. In raster databases, a mathematically defined operation used in image classification that removes long range (high-pass) or short range (low-pass) variations.

Font: One of the attributes describing the appearance of linear feature or text string.

1. For textural or spatial data, a complete set of text type of one size and typeface in which font designates a set of text characters of a particular style.
2. For spatial data, a user-defined set of instructions that determine, among other parameters, the appearance of a linear feature including dash and gap lengths, number of parallel lines, line widths, and spacing and description of embedded letters or symbols.

Format: The physical structure of an item. The order in which information is prepared and presented.

1. The arrangement of data for storage or display. A file format is the specific design of how information is organized in a collection or set of related digital data.
2. To divide (a disk) into marked sectors so that it may store data.
3. To determine the arrangement of (data) for storage or display.

FTP: File Transfer Protocol, a standardized way of transmitting files on the Internet.

G

Geocoding: In spatial databases, a coding process wherein a digital map feature is assigned an attribute to serve as a unique ID (tract number, node number) or classification (soil type, zoning category). In polygon processing, the polygon boundary that contains the coordinate pair of a data item (text label) is assigned the value of that data item as geocode. Geocodes are also referenced as "location identifiers".

Geodesy: Science or art of measuring the shape and size of the earth's surface, or large parts of it, as distinguished from surveying which deals only with limited tracts of the earth.

GIS: Geographic Information System. 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, and analysis; and 4) data reporting and product generation. It is useful to view GIS as a process rather than a thing. A GIS supports data collection, analysis, and decision making and is far more than a software or hardware product.

Gopher: A method of making menus of materials available on the Internet. A client/server type program requiring the user to have a Gopher Client program. Although there are still thousands of Gopher sites on the Internet, it is anticipated that they will be superceded by Hypertext (See Hypertext).

GPS: Global Positioning System. Developed for the military for navigation and surveying, the GPS relies on satellites (and ground stations) for precise determination of location. Although GPS can be used to determine location very precisely (within centimeters given the correct controls and proper use), it does not solve all the problems of locational determination of GIS databases.

Graphic User Interface: Software standard used to establish the menus, screens, dialog boxes, buttons, edit boxes, picklists, toggles, radio buttons, command input, and viewing screens used to communicate instructions to the computer and for the computer to communicate findings back to the user.

Graphic/Nongraphic Interface: Two-way interface between the spatial database (drawing) and the nongraphic DBMS table. Supports instructions sent from the spatial database requesting specific operations to be performed by the supporting DBMS, and instructions sent from the DBMS requesting specific transactions to be performed by the spatial database (i.e. change the color, fill pattern, width or thickness of associated spatial features).

GRASS: Geographical Resource Analysis Support System. A public-domain raster GIS modeling product of the U.S. Army Corp of Engineers's Construction Engineering Research Laboratory (USACERL)

Gray Scale: Generally refers to a monochrome ordering of 256 shades between black and white which are assigned to raster picture elements (pixels) according to reflected light, heat, and/or other relative intensity measurements. Most common digital display option for scanned black and white orthophotos.

GRID: Global Resource Information Database. A regular or nearly regular repeating pattern of equally sized geographic areas including squares, rectangles, equilateral triangle, or regular hexagon.

Grid: A geographic data model representing information as an array of equally sized square cells arranged in rows and columns. Each grid cell is referenced by its geographic x,y location.

Ground Control: Point on the surface of the earth with known coordinates as represented by some geographic grid reference system. The location of ground control points can be represented on maps and other cartographic products, and can serve as reference points with which to rectify the scale and accuracy of cartographic products to the actual area on the ground that is represented.

H

Header:

1. Titles displayed across the top of a database table that describe the content of each data field.
2. First record in a data file that contains identifying information and instructions that apply to all other components of the file or data set it contains.
3. In image files, a header stores information about format and/or registration coordinates.

Hierarchical: A logical structure that classifies information in a series of steps, starting with broad, simple classifications, and proceeding, in stages, to narrow, precise classifications.

High Level Language: Programming languages such as BASIC, PASCAL, or C++ that enable programmers to develop software applications using ordinary words and symbols rather than binary numbers. Also referred to as fourth generation languages. Typically a compiler transforms any one statement in such programs into many specific computer instructions.

HTML: HyperText Markup Language. A coding language used to create Hypertext documents for using the World Wide Web. You can specify that a block of text, or a word, is linked to another file on the Internet.

Hybrid: Combination of two different formats together. For example, a vector data overlay draped on top of a raster image.

Hydrology: Map data that describes the positions and characteristics of bodies of water.

Hypsography: Map data that describes the exact shape of the earth’s surface, usually in the form of contour lines, digital elevation models, or color shadings.

Hypertext: Any text embedded in a computer display that links to other documents. Other documents are displayed by clicking on a Hypertext Word.

I

Image:

1. Digital representation of spatial data stored in raster format. Scanned photos, maps, diagrams, or  remote sensing data (aerial photos, satellite scenes, radar telemetry) electronically stored as a raster (pixel) data set made up of either binary or integer values representing (singular or multiple) reflected light, heat, and/or other relative intensity measurements.
2. Exact copy of data in a file transferred to another medium.
3. One of the three kinds of Data (spatial, textural and image).

Image Processing: Computer techniques used to interpret and manipulate raster data including:

1. Enhancement - aid in the interpretation of an image by changing the display color and/or intensity of pixels (highlighting) that represent areas that share a common set (or range) of physical characteristics.
2. Rectification - Fitting the image to a map base by eliminating distortion due to the curvature of the earth, position of the camera or scanner, and/or varying terrain elevation.
3. Classification - Assigning pixies within an image to one category (land cover, soil category, etc.) or another according to their associated relative intensity measurements.
4. Data Merging - superimposing vector data on top of image data.

Indexing: Logically ordering information components by the values present in a key field. An identifier used to access stored information. DBMS table ID field of other data feature used to expedite locating a specific record (text, images, spatial) within a database.

Infrastructure: Refers to the roads, cables, wires, pipes, bridges, canals, reservoirs, and sewers that support economy and society. Infrastructure development and management are important in urban and rural areas at the local, state, regional, national, or international levels.

Inset Map: More detailed (larger scale) representation of a specific area on a map usually placed in an uncluttered portion of the same sheet as the smaller scale main map.

Interface:

1. Surface forming a common boundary between adjacent regions, bodies, substances, or phases.
2. Junction between two or more components of an information system. Typically, the link between the spatial database and nongraphic (DBMS) databases.
3. Point of interaction or communication between a computer and any other entity, such as a printer or human operator.

Internal File Format: The binary file format used internally by a specific GIS platform.

Interoperability: Communication between different computer systems. Seamless accessing and sharing of multiple data structures across multiple hardware platforms, operating systems and application software. For example, software A using hardware B being able to access and operate on data C.

Interpolation: Process of inserting, estimating, or finding a value intermediate to the values of two or more known points in space. Estimation of an elevation value at an unsampled point based on the known elevation values of surrounding points. Process of inserting, estimating, or finding a value intermediate to the values of two or more known points in space.

Intersect: The topological integration of two spatial data sets that preserves features that fall within the area common to both input data sets.

J

Join: Combing two tabular data sets into a single one based on a common field. Two tables with a common domain combined into a single table. SQL query that retrieves data from two or more sources at once based on matching field values.

JPEG: Joint Photographic Experts Group. A standardized image compression mechanism which can obtain high compression ratios, but may cause some data loss. Pixel values will be slightly different after decompression.

K

Key Map: A highly generalized map used to provide a contexture reference for retrieving more detailed spatial data sets for specific geographic areas.

L

Labels:

1. Text annotation posted on a map near a spatial feature.
2. Same as one wherein the source of the value of each label is from a linked database record.
3. Symbol or set of symbols identifying the contents of a file, memory, tape, or record.

LAN: Local Area Network. A communications system that typically consists of PCs with adapter cards, file servers, a network operating system, printers and gateways to departmental or corporate computers. Typically serves a small geographic area of a single building or campus of buildings.

Land Base: Spatial overlay comprised of multiple layers of primitive spatial features that provide a locational reference to other spatial features in the spatial database. It also includes a framework of competent survey data that provides a precision control network. The land base is also referred to as a base map.

LANDSAT: A series of satellites that produce images of the earth. The LANDSAT remote sensing satellite program was developed my NASA (National Aeronautics and Space Administration). LANDSAT data are provided in .BIL (band interleaved by line) or .BIP (band interleaved by pixel) formats.

Latitude: The first component of a spherical coordinate system used to record positions on the earth’s surface. Latitude indicates the angular distance north or south of the earth’s equator measured through 90 degrees. (See Longitude)

Layer: A subdivision of a CAD or GIS database containing related data. Layers can be visualized as transparencies which allow the user to view and analyze information selectively by theme. Some GIS build their databases as a series of layers covering a single area. Layers are fundamental to overlay analysis.

Legend: An explanation of the symbols, codes, names given to variables and other information appearing on a map drawing or chart. Includes a sample of each symbol, line pattern, shading, or hatching appearing on the map along with annotations describing the meaning of each.

Line: In spatial databases, a linear vector with only a start and endpoint, containing no intermediary (shape) turning points. A line feature is the alignment between two points representing within a spatial database a real world or theoretical feature, e.g., a road, stream or parcel boundary.

Line Smoothing: A variety of smoothing algorithms used to reduce file size by removing excessive turning points along a linear feature according to a user defined filter algorithm. (See Filtering).

Link (geometry): An element of geometry that connects nodes. In a polygon topology, a link defines a polygon edge. Links can contain vertices and true arcs, and can be represented as a line, polyline, or arc.

Link (external databases and object data): The connection between a drawing object and the database data. The link is stored in the linked drawing object and contains the link path name, the key, and link type.

LIS: Land Information System. Manual or computer-based information system used to store, retrieve, display, and plot spatial and textural data relating primarily to land features and characteristics. Addresses a wide range of existing natural and cultural aspects of land within a mapped area including property ownership, tax assessment, zoning, land use, vegetation, soils, geology, hazardous areas, noise zones, surface and subsurface hydrology. Can also include overlays that address infrastructure systems including transportation, sewer, water, storm, electric, cable, and telephone and storm drainage.

Location:

1. Distinct place in the real world.
2. Position defined by a set of coordinates within a spatial database (i.e. pole, property corner, reported crime incident.)
3. The storage space of digital data within an information storage system.

Longitude: The second component of a spherical coordinate system used to record east-west positions on the earth's surface, measured in degrees as the arc or position of the earth's equator intersected between the meridian of a given place and the prime meridian, which runs through Greenwich, England. (see Latitude)

Lookup Table:

1. Database table that assigns display parameters to each value in a field to generate thematic maps.
2. A list of values that are correlated to a range of other values. For example, according to a soil type name, reference to this table can identify the corresponding compressive strength, percolation, and erosion potential rating.
3. A file that correlates a user defined ID number permanently assigned to a spatial feature with machine readable ID numbe that is subject to occasional change.

M

MacOS: Operating System for Macintosh Personal Computers produced by Apple Computers.

Macros: Collections of frequently used commands which are grouped together in a file. Instead of entering commands individually, users can call the macro and the commands stored therein will be executed automatically. Macros may be stored in libraries.

Mainframe: Central Processing Unit, main memory, and control units of a computer typically housed in one large cabinet or in a number of smaller ones grouped together. The term only applies to large computers.

MapInfo Data Transfer Files or MIF/MID: A transfer system used by MapInfo that carries three types of information: geographic, attribute, and display.

Map Scale: The relationship between distance on a map and the corresponding distance on the earth's surface. Map scale is often recorded as a representative fraction such as 1:1,000,000 (1 unit on the map represents a million units on the earth's surface) or 1:24,000 ( 1 unit on the map represents 24,000 units on the earth's surface). The terms "large" and small refer to the relative magnitude of the representative fraction. Since 1/1,000,000 is a smaller fraction than 1/24,000, the former is said to be a smaller scale. Small scales are often used to map large areas because each map unit covers a larger earth distance. Large-scale maps are employed for detailed maps of smaller areas.

Memory:

1. Unit of a computer that preserves data for retrieval.
2. Capacity for storing and remembering information for subsequent reference.
3. An organized set of locations in which a computer can store and find data instructions. Such capacity stored in Random Access Memory microchips (RAM) is referred to as virtual memory.

Menu: Options for command input by computer users rather than typing instructions at the command line. Menus come in many forms including permanent screen menu squares, pull-downs, popups, sliders, icons, cursor, picklists, dialog and toolbar buttons, as well as printed tablet menus and cursor buttons on digitizing (mouse) devices.

Mercator Projection: A map projection designed by Gerardus Mercator, where the earth’s surface is drawn as it would appear if projected on a cylinder wrapped around the earth.

Merge:

1. Combine items from two or more similarly ordered sets into one set that is arranged in the same order.
2. Splice separate but adjacent mapped areas into a single data set.
3. Annotate spatial features with attribute values retrieved from selected fields within linked DBMS records. Typically users can control the size, angle, style, color, font, and offset of these posted labels.

Metadata: Information describing a data set. A digital maps;s metadata might state its scale, revision date, author, accuracy standards, and other pertinent information.

Microcomputer: Very small computer, such as a laptop or personal computer, built around a microprocessor as its CPU and designed to be used by one person at a time; smaller than a minicomputer.

MicroStation Design Files or DGN: The internal format and transfer standard used by Bentley Systems Inc.’s MicroStation.

Minicomputer: A medium sized computer, usually fitting within a single cabinet, serving the needs of multiple users within a small organizational unit. Has more memory and a higher execution speed than a microcomputer. Also referred to as a workstation or midrange.

MIPS: Millions of Instructions Per Second. A CPU related performance measurement.

Modeling:

1. Applying structured rules and procedures to one or more spatial database overlays to conduct spatial and/or network analysis to derive new information to aid in problem solving and planning.
2. Schematic description of a system, theory, or phenomenon that accounts for its known or inferred properties and may be used for further study of its operational characteristics.
3. Process of simulation, prediction and description involving changing the parameters and generating/communicating new model results. Using spatial or network overlays to simulating a process to predict outcomes to what-if scenarios.

Modem: Abbreviation for MODulator and DEModulator, adevice that converts data from one form into another.

1. From one form usable in data processing to another form usable in telephonic transmission.
2. Send and receive information over communication lines between computers, usually over telephone lines.

N

Network: A system of spatially or functionally interconnected geographic features such as a system of roads, wires, pipes, or cables. With respect to computers, networks describe communication connections among machines.

Network Analysis: A range of techniques employed by engineers and planners to study the properties of networks including connectivity, capacity, and rates of flow. Network analysis can be used to estimate the capacity of a road network or to plan for additions to an electrical distribution system.

Network Routing: In transportation networks, this refers to highlighting all node and link features along the optimal path between a starting point and one or more destinations, either in terms of least distance, travel time, or other prescribed performance criteria.

Network Topology: The representation of a linear network by links and, sometimes, nodes. For example, a network topology can represent pipelines, streets, electrical transmission lines, and rivers.

Network Tracing: In utility networks, this refers to highlighting all node and link features within a gravity of pressure network that are both physically and logically connected to a test point within the network according to a specified set of rules.

Node: A link endpoint that can be represented as a block or point object.

Node Topology: A description of the relationship of point objects that describe a common geographic feature. Examples of node topologies include point sources of pollution and road signs.

Nongraphic Database (also Nonspatial): Set of tabular data records, each record containing multiple data fields. In the context of spatial databases, one of these fields is the Unique ID Number of a corresponding map feature.

Northing: The north-south, Y, coordinate in a rectangular coordinate system.

O

On-The-Fly: Temporary performance of a calculation when needed. An instruction that is transparently invoked by the user according to conditions encountered during a transaction. Automatic Boolean operations that add, modify or skip certain processing steps under a particular set of conditions. For example, when adding a new spatial feature, the ID number of the previously encoded feature is defined along with the default rules for sequentially generating the next ID number to be used, modified or ignored.

Operating Systems: The software systems that manage the interaction between users and hardware. Operating systems are employed by users to tell a computer what to do with the resources at its disposal in order to run programs, store data, or send files to peripherals such as plotters and printers.

Optical Fiber: Bundles of transparent glass or plastic strands able to transmit billions of bits of information per second in the form of light pulses generated by lasers. Telephone companies are systematically replacing conventional copper wire (metallic) with these enclosed thin glass wires, vastly increasing the variety and quality of services that can be offered to consumers. In addition to speed, optical systems are not subject to interference from random radiation in the environment as are metallic systems.

Orientation: Attribute of spatial features that describes the angle at which it is turned from its normal north south axis. Applies particularly to text or symbols, two point line features, and entire blocks of spatial features. For example, a water hydrant with an orientation of 30 degrees would be viewed with a declination of 120 degrees from the horizontal plane.

Orthophotograph: An aerial photograph in which the displacement of images have been removed and may also form the base map for many GIS programs

Overlay: Something that is laid over or covers something else.

1. In a manual graphic information system, a transparent sheet containing graphic information, such as labels, symbols or colored areas, defined in a manner to expedite being viewed and interpreted in conjunction with other data overlays with a common coordinate system.
2. In an automated spatial information system, same as a manual system except that all overlays are in a digital format for viewing and interpretation on a CRT screen. Each overlay defines a specific aspect of the spatial database.
3. Typical overlays could include land use, soils, watershed boundaries or drainage system overlays, each of which is a single or set of multiple layers within the spatial information system.
4. Also refers to the intersection of two polygon layers to make a third composite overlay (i.e. soils overlaid with land use to define runoff conditions).

Overshoot: Situation where a digital line extends past the intended boundary line. This extension past the intended juncture point is called a dangle.

P

Parallel Communications: Data transmission wherein multiple wires simultaneously carry one data bit at a time greatly increasing the rate that data can be sent over a single wire. However, distance restrictions between components limit their use to being internal to a single device or between devices within a single room.

Parcel: A portion of the earth defined by a boundary inside of which certain assigned rights apply regarding occupancy and/or use of land, air or water. Can also include linked attributes that define the rules and conditions for exercising these rights.

Parent Child Links: Technique wherein attribute lists in two different tables are joined together to function as a single DBMS table. When indexing on a common ID record in both the parent (core) and child (subordinate) table, three different kinds of links can be initiated:

• One-to-one: For every record in the parent table there is one and only one record in the child table with a matching ID in the indexing fields (i.e.Parcel Record and Water Customer Record - common field: Parcel Number).
• One-to-Many: For every record in the parent table, there may be one or more records in the child table with a matching ID in the indexing fields (i.e. Building record and Asbestos incidence record - common field: Building #).
• Many-to-One: For every record in the child table, there is more than one record in the core table with a matching ID in indexing fields (i.e. Parcel Record and Zoning Ordinance Description - common field: Zoning Ordinance Number).

PCX: PC Paintbrush Exchange. A widely used raster format.

Peripherals: Items of computer equipment such as plotters, printers, scanners, digitizers, and graphics displays. Although essential to a complete GIS, these pieces of equipment are considered peripheral to central computer resources such as the processor, memory, keyboard, and display screen.

Photogrammetry: Uses aerial photographs to produce planimetric and topographic maps of the earth’s surface and of features of the built environment. Effective photogrammetry makes use of ground control by which aerial photographs are carefully compared and registered to the locations and characteristics of features identified in ground-level surveys.

Pixel: Abbreviation for Picture Element, the smallest nondivisible image-forming unit of a plot or video display. Each cell can have assigned attributes, in addition to color. In raster processing, pixels refer to a single cell within a matrix of grid cells.

Planar Coordinate System: A coordinate system drawn on a flat surface, or plane. Planar coordinates are usually expressed as pairs of rectangular X,Y values.

Planimetric Map: Horizontal depiction of map features on a two-dimensional plane without any reference to contours or topographic relief. Typical features defined within a planimetric map include such natural and cultural features as streams, roads, shorelines, waterways, building footprints, reservoirs, bridges, roadways, overpasses, sidewalks and parking lots.

Platform: A term for computer hardware, including microcomputers, workstations, and mainframe computers. When discussing software, platform independence implies the software can be run on any computer.

PLSS: Public Land Survey System. A reference scheme for recording property ownership by section, township, range, and aliquot parts (half or quarter sections) in the United States. The PLSS was laid out during the settlement of the country, dividing land areas into townships of 36 one-square mile sections.

Point: Single X,Y (optionally Z) location in space. Dimensionless geometric feature having no other spatial properties except location. Many different natural and man-made features are modeled as points in a spatial database including trees, hydrants, poles, buildings, etc.

Polygon: A coverage feature class used to represent areas. A polygon is defined by the arcs that make up its boundary and a point inside its boundary for identification. Polygons have attributes that describe the geographic feature they represent.

Polygon Topology: The representation of areas and area relationships using links and enclosed areas. Polygon topologies can also include nodes and centroids. Examples of polygon topologies are land use and land cover maps, political boundaries, parcels, and soil types.

Precision: Refers to the level of measurement and exactness of description in a GIS database. Precise locational data may measure position to a fraction of a unit. Precise attribute information may specify the characteristics of features in great detail. It is important to realize, however, that precise data---no matter how carefully measured---may be inaccurate. Therefore, a distinction is made between precision and accuracy.

Prime Meridian: The line of longitude that runs through Greenwich, England, used as the origin (zero point) for longitudinal measurements.

Projection: A system to portray all or part of the earth, which is an irregular sphere, on a planar, or flat surface.

Prototype Model: Develop a test model to determine the feasibility of proposed data structures, software, hardware, communications, interfaces, and procedures. Typically involves the assembly of a very small geographic portion of the overall project area but the maximum range of data types and procedures anticipated in the development and operation of the ultimate geographic data model.

Pseudo Node: A node at where two, and only two, arcs intersect, or a single arc that connects with itself. Pseudo nodes can be used to subdivide an arc to mark the location of an attribute change along a linear feature.

Q

Quarter-Quad: Refers to a map sheet size that is one-quarter of a 7.5 minute USGS quadrangle. DOQQ is a digital orthophoto quarter quad, a map product @ 1=1,000’ used by the USGS and many statewide programs.

Query: A logical search specification finding spatial features with linked records that contain matching geographic and/or nongraphic attributes.

R

Raster: Raster data takes an evenly spaced grid (like a piece of graph paper) and places a value in each square, or cell. Raster data is best suited for continuous data such as slope, rainfall, or the amount of light reflecting off the ground (as in a photograph). Aerial photographs and satellite images are examples of raster images used in mapping.

Record:

1. An assemblage of textural data within a DBMS table and/or drawn statement as a means of preserving knowledge.
2. Collected and preserved data describing a particular subject.
3. A row (series of field values) in a database table. In a spatial database, each graphic feature may be linked to one or more records in one or more tables.
4. A collection of fields or other sub-portion of computer file treated as a data unit.

Rectification: A set of techniques for removing data errors through calculation or adjustment. In image processing, computer programs that remove distortion within a digital image, aerial photography or remotely sensed data by removing parallax errors due to relief (high ground being closer to the camera than low lying areas), camera tilt, corner and other distortions.

Real-time: Computations or data communications that occur instantaneously or nearly so with the execution of a command or transaction.

Relate: To establish or demonstrate a connection between two or more things. In spatial analysis, establishing a temporary connection between records in two different tables using an item common to both. An indexing value in a field, both in the core table and the child table, that makes it possible to join the two so that they can operate as one combined table.

Relational Database: Information storage system in which there is an association between two or more things. Organized according to relationships between data items. Collection of tables that are logically associated to each other by shared common attributes. Entering the table name, attribute name, and the value of the primary key, any data element or set of elements can be retrieved. Consists of table rows and columns.

Remote Sensing: Using a recording device not in physical contact with the surface being analyzed including:

1. Using sensors sensitive to various bands of the electromagnetic spectrum.
2. Assessing its spectral image without having the sensor in direct contact with the surface.
3. Interpreting environmental conditions at, below and above the surface of the earth, typically by processing images from an aircraft (i.e. aerial photography), satellite imaging (i.e. LANDSAT), or radar.

Resolution: The smallest detectable distance between features recorded on a digitizer, displayed on a graphics screen, or drawn by a plotter.

1. "Display Resolution"; The density of the pixels that compose an image. The greater the number of pixels per square inch of screen, the greater the resolution. In print, resolution is measured in dots per inch (dpi).
2. "Spatial Resolution" The smallest possible map feature that can be accurately displayed at a specified map scale. For example, in a 1:24000 scale map, a 50-foot distance between a roadway and railroad track centerline is one fortieth of an inch. Since the thinnest pen line width is presumed to be one fortieth of an inch, it is impossible to accurately represent the alignment of these two centerlines and still have a visible gap between them. To do this takes a smaller map scale (< 1:24000).

Rubber Sheeting: Spatial database editing software that attempts to correct errors by stretching a map to fit known control points or monuments. Mathematical method to stretch or warp images to match existing vector data. Forces a digital map to fit a designated base. To implement, XY values of known coordinates within the survey control network are entered in conjunction with screen selections of the corresponding locations within the map overlay to be rubber sheeted. Each coordinate within the map overlay being processed is moved to the location of the prescribed control coordinate.

S

Scale: The proportion or ratio between a map measurement and the corresponding measurement in the real world. Map scale is usually expressed as a ratio, such as 1:24,000, which means that a measurement of one unit on the map represents 24,000 units in the real world.

Scanning: A process by which data and maps are converted to digital form using optical or video equipment. Scanning differs from digitizing in that entire pages of data or map sheets are captured as images all at once.

Schema:

1. In a textural database, organization of relationships within a database system including field names, header descriptions, size and type, and indexing configurations.
2. In a spatial database, all of the above instructions needed tolink attribute records to spatial features as well as other tables.
3. In general, a set of organizational rules imposed on a body of data to assist in explaining its content and/or guiding response.

Screen Text: Text data actually visible on the display monitor. In nongraphic data, displays of text records, tabulations, and other text documents. In spatial database, text features used to annotate other map features such as road names, node numbers, pipe sizes and town names. In user interface, text visible in side, pull-down, pop-up, dialog and icon menus and picklists.

SDTS: Spatial Data Transfer Standard for transferring data between multiple geographic data management systems. Includes metadata that addresses internal spatial reference, completeness, positional and attribute accuracy, logical consistency, and data dictionary.

Serial Communications: Digital transmissions in which information is transferred one bit at a time over a single wire or channel. In synchronous communications, blocks or packets of bits contain data are sent according to an established timing sequence. Serial lines are commonly use to connect peripheral devises to computer networks.

Single-Precision Accuracy: Refers to a level of coordinate accuracy based on the number of significant digits that can be stored for each coordinate. Single-precision numbers store up to 7 significant digits for each coordinate, retaining a precision of +/- 5 meters in an extent of 1,000,000 meters. (See also Double-Precision Accuracy).

Situs Address: The proper or original position of a specific location. An element that designates a fixed site, such as the address of a property or building.

Sliver Polygon:

1. Gap between two lines created erroneously by a scanner and its raster-vector software.
2. Refers to polygons formed when two adjacent polygons do not abut along a single common line resulting in the creation of a very thin polygon being present between the larger two.

Snap Radius- Used to eliminate gaps (undershoots) and dangles (overshoots) in boundaries as a preparatory step to building polygon topology. A distance parameter defining the maximum gap or dangle that will be adjusted. For example, if a snap radius of 2 is prescribed, all gaps and dangles greater than two model units in size will not be adjusted. Instead their locations will be marked for subsequent editing. Once all gaps and dangles are less than 2 model units, software snaps all end points of all contiguous polygon boundary segments to a single locations according to first-point-wins, averaging, and other algorithms.

Spatial Analysis:

1. Methods used to explore the spatial relationships between features both real and theoretical.
2. Process of extracting or creating new information about a set of geographic features; techniques to determine the distribution of a spatial feature(s); and the relationships between two or more features, the location of, proximity to, and orientation of these features in space.
3. Study of the locations and shapes of geographic features and the relationships between them.

Spatial Data: One of the three kinds of data (spatial, textural and image). Spatial data is categorized according to the following feature types:

1. Zero-dimensional features: Primitive Points; topological Node.
2. One-dimensional features: Primitive Lines, Strings (multiple nonbranching lines), arcs (mathematically defined curve; topological Links, chains, and rings.
3. Two-dimensional features: Polygons defining enclosed areas, Pixels, and Grid Cells.

Spatial Query: Function that allows a user to find, display, and/or isolate attributes records linked to map features located within a defined area of interest - window, circle, polygon or trace.

Spherical Coordinate System: A coordinate system measured on the surface of a sphere, usually expressed as angular distances.

SQL: Structured Query Language. A computer industry-standard syntax language for querying and manipulating most relational database management systems (DBMS). Commands can be embedded within a programming language to interface to a database or used interactively.

State Plane Coordinate System: System of X,Y coordinates defined by the USGS for each state. Locations are based on the distance from an origin point defined for each state.

Synchronous: Data transmitted along a communication line in a continuous stream via serial or parallel lines according to an established timing sequence. Typically used in high-speed local area networks (LANs) and mainframe computer configurations.

T

TCP/IP: Transmission Control Protocol/Internet Protocol. The standard for communication from one Internet computer to another.

Terminal: Device often equipped with a keyboard and a video display, through which data or information can enter or leave a computer system.

Thematic Map: Representation of data to show trends or patterns. Data is highlighted or emphasized using properties and values, such as color and line width.

Theme: Set of related geographic features, such as streets, parcels, or rivers, and the attributes (characteristics of those features). Geographic features logically organized into groups. Thematic map emphasizing a single environmental aspect such as soils, land cover, or geology.

TIF: Tagged Image File format. A widely used raster format.

TIGER: Topologically Integrated Geographic Encoding and Referencing File. This is a type of digital map developed by the U.S. Bureau of the Census to support the 1990 population census.

Tile: A subset of a GIS database that contains information about one sub-area of the overall digital map. Tiles are an effective way of dividing a continuous map into units that can be easily created, edited, and analyzed. The terms tile and facet are synonymous.

Tolerance: Leeway for variation from a standard. Permissible deviation from a specified value of a structural dimension often expressed as a percent. Parameter for defining a limiting distance for an operation. For example, a snap tolerance for 2 units apart means that any two endpoints less than 2 units apart will be moved to at a single point location.

Topographic Feature: Spatial representation of the surface features of a place or region on a map, indicating their relative positions and elevations.

Topology: A set of defined relationships between links, nodes, and centroids. Topology describes how lines and polygons connect and relate to each other, and forms the basis for advanced GIS functions, such as network tracing and spatial analysis.

Transportation Network: System of interconnecting nodes and links that represent intersections of roadways, railroads, transit lines, or other forms of transportation systems.

U

Undershoot: Situation where a digital line does not meet up with its intended boundary line. The space between the two is called a gap.

Union: A set, every member of which is an element of one or another of two or more given sets. The combination of two spatial data sets where the result includes all of the features of the two inputs.

UNIX: Industry standard operating system (OS) developed as a joint venture between University of California at Berkeley and the AT&T Bell Laboratories. A multi-user multitasking OS operates on a wide variety of computer systems from micro to mainframe. Written in C, it carries with it C's inherent transportability that enables it to be easily ported to many different hardware platforms. In addition to their own proprietary operating system, many hardware vendors offer UNIX as an auxiliary OS further expediting the free flow of data between multiple hardware platforms.

User Interface: Software components that expedite its intuitive and competent use. Options for command input by computer users rather than typing instructions at the command line. User interface can take on many forms including screen, pull-down and pop-up menus; icons, dialog buttons, toggles and picklists; toolbar buttons; printed tablet menus and cursor buttons on digitizing (mouse) devices. Also includes productivity enhancements, error messages, error trapping, on-line help, MACROS (and their prompts), sample databases, tutorials, manuals, and other documentation. (See On-the-fly).

UTM: Universal Transverse Mercator. A specific implementation of the transverse mercator projection, designed for common usage around the world. The UTM system divides the world into 60 east-west zones, each of which is six degrees of longitude wide. Each zone is projected individually.

V

Vector: Vector data is the storage of X, Y, Z coordinates connected to form points, lines, areas, and volumes. Vector data is best suited to store discrete, well-defined data that can clearly be delimited. Location of oil wells (points), street centerlines (lines), timber stands (areas), and groundwater tables (volumes) are good candidates for vector storage.

Viewer: A read-only stand-alone software system that supports the display, manipulation, and query of spatial databases. Commercial products that enable user reference and analyzed spatial databases prepared by a full function read-write product within the same product line. Typically has a user interface simpler than full function products. Supports rich command set but less than that available in the full function product.

W

WAN: Wide Area Network that typically interconnects mainframe, mini-computers, and PCs providing communication links within areas larger than that served by a Local Area Network (LAN).

Warping: A method which can overcome some of the problems of edge matching. It can also be used to resolve registration problems arising from digitizing source maps of different scales, different projections, and varying coordinate systems.

Window:

1. Rectangular portion of a larger mapped area selected for display, for example, a rectangle surrounding Colorado and ignoring other areas in a databases covering the Western U.S.
2. The defined outline of a section of an image which can be viewed simultaneously with other portions of the same or other images.
3. In spatial queries, a type of boundary for creating a selection set of all spatial features and their linked DBMS records.
4. A portion of the graphic user interface that enables you to open, close, resize, or relocate a rectangular area on the computer screen that is displaying information other than that being displayed by the spatial database (i.e. DBMS Table, edit, query, report display screens; documents in a word processor, image in a document management system).

Z

Z-Axis: Third or height axis of a three-dimensional Cartesian coordinate system that crosses the XY axis plane at a 90-degree angle. The Z-axis is normally used to represent elevation above sea level.

Zoom: Computer screen function to enlarge (zoom in) or decrease (zoom out) proportionately the size of the display features shown on the computer screen by rescaling the image. Common term in both CAD and GIS for changing the scale and or extents of a map. For example, zooming in shows more detail while zooming out shows less detail. 

Acronyms

A

ACSM: American Congress on Surveying and Mapping

AI: Artificial Intelligence

AM/FM: Automated Mapping / Facilities Management

AML: ARC Macro Language

ANSI: American National Standards Institute

API: Application Program Interface

ASCII: American Standard Code for Information Interchange

ASIC: Application Specific Integrated Circuit

ASPRS: American Society of Photogrammetry and Remote Sensing

ATM: Adaptive Triangular Mesh

AVHRR: Advanced Very High Resolution Radiometer

B

BBS: Bulletin Board Service

BIT: Binary Digit

BIL: Band Interleaved by Line

BIP: Band Interleaved by Pixel

BLOB: Binary Large Object

BLPU: Basic Land and Property Unit

BLUE: Best Linear Unbiased Estimate

BM: Bench Mark

BPS: Bits Per Second

BSQ: Band Sequential

BSU: Basic Spatial Unit

C

CAD: Computer Aided Design, Dispatch, or Drafting

CAM: Computer Aided Mapping or Manufacturing

CAMA: Computer Assisted Mass Appraisal

CASE: Computer Aided Software Engineering

CCT: Computer Compatible Tape

CD-I: Compact Disc-Interactive

CD-R: Compact Disc, Recordable

CD-ROM: Compact Disc, Read Only Memory

CGI: Common Gateway Interface

CGM: 1) Computer Graphics Metafile; 2) Circle

CIR: Color Infrared

CMS: 1) Cadastral Mapping Specialist; 2) Conversational Monitor System

COBOL: Common Business-Oriented Language

COGO: Coordinate Geometry

COM: Component Object Model

CORBA: Common Object Request Broker Architecture

CPU: Central Processing Unit

CSSM: Content Standards for Spatial Metadata

D

DASC: Data Access and Support Center

DB: 1) Database, 2) Decibel

DBMS: Database Management System

DDE: Dynamic Data Exchange

DDL: Data Definition Language

DEM: Digital Elevation Model

DES: Data Encryption Standard

DGM: Digital Geospatial Metadata

DGPS: Differential Global Positioning System

DIF: Data Interchange Format

DIGEST: Digital Geographic Information Working Group Exchange Standard

DIME: Dual Independent Map Encoding

DIP: Digital Image Processing

DLG: Digital Line Graph

DMS: Direct Memory Addressing

DML: Data Manipulation Language

DMS: Degrees Minutes Seconds

DOS: Disk Operating System

DOQ: Digital Orthophoto Quadrangle

DPI: Dots Per Inch

DRAM: Dynamic RAM

DRF: Digital Raster File

DRG: Digital Raster Graphic

DTD: Digital Terrain Data

DTM: Digital Terrain Model

DWG: Drawing Files (AutoCAD)

DXF: Digital Exchange Format (Autodesk)

E

EDI: Electronic Data Interchange

EDIFACT: Electronic Data Interchange For Administration, Commerce and Transport

EDM: Electronic Distance Measurement

EDO: Extended Data Out

EIDE: Extended Integrated Device Electronics

EISA: Enhanced Industry-Standard Architecture

EOS: Earth Observation Satellite

EOSAT: Earth Observation Satellite (company)

EPS: Encapsulated Postscript

ERIN: Environmental Resources Information Network

ESRI: Environmental Systems Research Institute

ETM: Enhanced Thematic Mapper

F

FAT: Feature Attribute Table

FCC: Federal Communications Commission

FDD: Floppy Disk Drive

FDDI: Fiber Distributed Data Interface

FDHD: Floppy Disk High-Density

FGCC: Federal Geodetic Control Committee

FGDC: Federal Geographic Data Committee

FIPS: Federal Information Processing Standard

FRAMME: Facilities Rulebased Application Model MTG Environment(Intergraph)

FSA: Farm Services Agency, USDA

FTP: File Transfer Protocol

G

GB: Gigabyte

GBF: Geographic Base File

GFIS: Geographic Facilities Information System (IBM)

GIF: Graphics Interchange Format

GIS: Geographic Information System

GLONASS: Global Orbiting Navigation Satellite System (Russia)

GMT: Greenwich Mean Time

GPR: Ground Penetrating Radar

GPS: Global Positioning System

GRASS: Geographic Resource Analysis Support System

GRF: Geographic Reference File

GRID: Global Resource Information Database

GRS: Geodetic Reference System

GSD: Ground Sample Distance

GUI: Graphical User Interface

H

HARN: High Accuracy Reference Network

HDD: Hard Disk Drive

HP2: Hewlett Packard Graphics Language 2 (HPGL2 file)

HRV: High Resolution Visible

HSB: Hue, Saturation, Brightness

HSV: Hue, Saturation, Value

HTML: HyperText Markup Language

HTTP: Hypertext Transfer Protocol

HUA: Hydrologic Unit Area

HUC: Hydrologic Unit Code

I

IAAO: International Association of Assessing Officers

IAC: Inter-application Communication

ICES: Initial Graphics Exchange Specifications

IDE: Integrated Device Electronics

IEC: International Electrotechnical Committee

IFF: Interchange File Format

IGDS: Interactive Graphics Design Software (Intergraph)

IGES: International Graphics Exchange Specification

IHS: Intensity, Hue, Saturation

IP: Internet Protocol

IR: Infrared, Imaging Radiometer

IRDS: Information Resource Dictionary System

ISA: Industry Standard Architecture

ISDN: Integrated Services Digital Network

ISO: International Standards Organization

IT: Information Technology

IVHS: Intelligent Vehicle Highway System

J

JFIF: JPEG File Interchange Format

JPEG: Joint Photographic Experts Group

K

KAM: Kansas Association of Mappers

KB: Kilobyte (1,000 bytes)

KCC: Kansas Corporation Commission

KDHE: Kansas Department of Health and Environment

KDOR: Kansas Department of Revenue

KDOT: Kansas Department of Transportation

KGS: Kansas Geological Survey

KM: Kansas Mapper designation, Kilo Meter

KWO: Kansas Water Office

L

LAN: Local Area Network

LANDSAT: Land Satellite

LAT: Latitude

LAT/LON: Latitude / Longitude

LCD: Liquid Crystal Display

LED: Light-Emitting Diode

LIPS: Logical Instruction Per Second

LIS: Land Information System

LPI: Lines Per Inch

LRD: Low Resolution Data

LU: Land Use

LUT: Look-up Table

M

M: Meter

MAF: Master Address File

MAGIC: MidAmerica GIS Consortium

MB: Megabyte (1,000,000 bytes)

MDL: Microstation Development Language (Bentley)

MDS: Meta Data Standards

MGE: Modular GIS Environment (Intergraph)

MHZ: Megahertz

MIPS: Millions of Instructions Per Second

MMU: Minimum Mapping Units

MN: Magnetic North

MO: Map Objects (ESRI)

MOSS: Map Overlay and Statistical System

MPEG: Motion Picture Experts Group

MS: Micro Soft

MSA: Metropolitan Statistical Area

MSL: Mean Sea Level

MSS: Multi-Spectral Scanner

N

NAD: North American Datum

NAPP: National Aerial Photography Program (NAPP)

NAVD: North American Vertical Datum

NDIS: Network Driver Interface Specification

NFS: Network File System

NGD: National GeoSpatial Database

NGS: National Geodetic Survey

NIST: National Institute of Standards and Technology

NITF: National Image Transfer Format

NRCS: Natural Resources and Conservation Service, USDA

NS: Nanosecond

NSDI: National Spatial Data Infrastructure

NTF: National Transfer Format

NWI: National Wetlands Inventory

O

OCR: Optical Character Recognition

ODBC: Open DataBase Connectivity

OGC: Open GIS Consortium

OGIS: Open GeoData Interoperability Specification

OLE: Object Linking and Embedding

OMG: Object Management Group

OOP: Object-Oriented Programming

OS: Operating System

OSF: Open Software Foundation

OSI: Open Systems Interconnection

OSTF: Ordinance Survey Transfer Format

P

PAT: Point/Polygon Attribute Table

PC: Personal Computer

PCI: Peripheral Component Interconnect

PCMCIA: Personal Computer Memory Card International Association

PDA: Personal Digital Assistant

PDD: Portable Digital Document

PDF: Portable Document File

PDN: Public Data Network

PHIGS: Programmer Hierarchical Interactive Graphics System

PIM: Personal Information Manager

PIN: 1) Parcel Identification Number, 2) Personal Identification Number

PIXEL: Picture Element

PKM: Professional Kansas Mapper

PLS: Professional Land Surveyor

PLSS: Public Land Survey System

POSIX: Portable Operating System Interface

PPI: Pixels Per Inch

PPRT: Post Processing Real Time (DGPS)

PROM: Programmable Read-Only Memory

PVD: Property Valuation Division, KDOR

Q

QUAD: Quadrangle

R

RADAR: Radio Detecting and Ranging

RAM: Random Access Memory

RDBMS: Relational DataBase Management System

RGB: Red, Green, Blue

RIP: Raster-Image Processor

RISC: Reduced-Instruction Set Computer

RLC: Run-Length Compressed

RLE: Run-Length Encoding

RMS: Root Mean Square

ROM: Read Only Memory

RS: Remote Sensing

RTK: Real-Time Kinematic (GPS)

RTP: Real-Time Positioning

RTV: Real-Time Video

S

SCSI: Small Computer Systems Interface

SDB: Spatial DataBase

SDE: Spatial Database Engine (ESRI)

SDES: Spatial Data Exchange Standard

SDML: Spatial Data Manipulation Language

SDTS: Spatial Data Transfer Standard

SID: Scanned Image Data

SIF: Standard Interchange Format

SIG: Special Interest Group

SIMM: Single In-Line Memory Module

SINES: Spatial Information Enquiry Service

SLF: Standard Linear Format

SNA: Systems Network Architecture

SPCS: State Plane Coordinate System

SPOT: Satellite Pour l'Observation de la Terre

SQL: Structured Query Language

SQL/MM: Structured Query Language/ Multi Media

SRG: Standardized Raster Graphic

STED: Standard for the Exchange of Data

SVGA: Super Video Graphics Array

SYMAP: Synagraphic Mapping

S/N: Signal to Noise

T

TAG: Tabular and Graphic

TCP/IP: Transmission Control Protocol/ Internet Protocol

TIFF: Tagged Image File Format

TIGER: Topologically Integrated Geographic Encoding and Referencing

TIN: Triangulated Irregular Network

TM: 1) Thematic Mapper, 2) Transverse Mercator

TVP: Topological Vector Profile

U

UPS: Uninterruptible Power Supply

URISA: Urban and Regional Information Systems Association

USDA: United Stated Department of Agriculture

USGS: United States Geological Survey

USLM: United States Land Monument

USMM: United States Mineral Monument

UTM: Universal Transverse Mercator

V

VABM: Vertical Angle (elevation) Bench Mark

VGA: Video Graphics Array

VI: Vegetation Index

VPF: Vector Product Format

VRAM: Video RAM

VRF: Vector Relational Format

VRML: Virtual Reality Markup Language

W

WAIS: Wide Area Information Service

WAN: Wide Area Network

WGS: World Geodetic System

WIS: Watershed/Wetlands Information System

WORM: Write Once, Read Many

WRS: World Reference System

WWW: World Wide Web

File Entensions

.ADF: Arc Data Files

.AI: Adobe Illustrator subset of .EPS

.ARG: Arc digitized Raster Graphic

.APR: Arc View Projects

.ASC: ASCII text file

.BAK: Backup copy of a file that has been edited (also BK)

.BAS: BASIC program file

.BAT: Batch job (file of commands, in MS-DOS)

.BIL: Band Interleaved by Line

.BIP: Band Interleaved by Pixel

.BMP: Bitmap (Windows or OS/2 graphics)

.C: C program file

.CDR: Vector graphics (CorelDraw)

.CIB: Controlled Image Base, panchromatic images

.CMD: File of commands (in OS/2)

.COM: Command file (smaller version of .EXE

.CPP: C++ program file

.DXF: Drawing Exchange Format

.DOC: Document file (ASCII or Microsoft Word)

.DLG: Digital Line Graph

.DLL: Dynamic link library

.DWG: AutoCAD Drawing Format

.EPS: Vector graphics, encapsulated PostScript format

.EXE: Executable file (machine-language program)

.FRM: Form design (Visual Basic)

.GIF: Bitmap graphics file (CompuServe format)

.HLP: Help file

.ICO: Icon (Windows or OS/2)

.INI: Initialization file (configuration settings)

.LOG: Log of installation or usage (various software)

.MAK: Makefile (Visual Basic and other environments)

.MID: MIDI digitized music file

.PAS: Pascal program file

.PCD: Bitmap graphics file (Photo CD format)

.PCX: Bitmap graphics file (Zsoft format)

.PIF: Program information file (Windows)

.PRJ: Project file (various compilers)

.PS: PostScript printable file

.SYS: Component of the operating system

.TIF: Bitmap graphics file (TIFF format)

.TTF: True Type font

.TMP: Temporary file

.TXT: ASCII text file

.WAV: Sound wave file

.WKS: Lotus 1-2-3 worksheet file (also WK2, WK3, etc.)

.WP:; WordPerfect document (also WP5, WP6 )

.WRI: Document file (Windows Write)

.XLS: Excel worksheet file

.ZIP: File compressed with different compression software

Bibliography

Autodesk AutoCAD MAP Users Guide Glossary

White Paper-Geographic Data: How to Choose and Create a Data Set for your GIS Projects

Barron's Business Guide

Dictionary of Computer and Internet Terms

ESRI GIS Glossary

Intergraph MicroStation PC Glossary

University of Texas GIS Glossary

URISA GIS Working Glossary