GIS Dictionary

[environmental GIS] Acronym for United States Geological Survey. A scientific agency of the U.S. government, part of the Department of the Interior. The U.S. Geological Survey is a fact-finding research … Read more

[federal government] The U.S. government agency responsible for maintaining the National Spatial Reference System (NSRS), the national coordinate system of the United States.

[standards] Acronym for Universal Description, Discovery, and Integration. An XML-based standard for creating online directories of Web services.

[programming] Acronym for user interface. The portion of a computer’s hardware and software that facilitates human interaction. The UI includes items that can be displayed on screen, and interacted with … Read more

[programming] A custom button, tool, text box, or combo box created with VBA.

[programming] Acronym for Unified Modeling Language. A modeling language that uses a series of diagrams to model the objects in a system.

[ESRI software] In Survey Analyst – Cadastral Editor, a cadastral fabric editing command that undoes the parcel generated from the build parcel command.

[computing] Acronym for Universal (or Uniform) Naming Convention. A PC format for specifying the location of resources on a local-area network (LAN). UNC follows the format \\servername\shared_resource_path

[uncertainty] The degree to which the measured value of some quantity is estimated to vary from the true value. Uncertainty can arise from a variety of sources, including limitations on … Read more

1 [cadastral and land records] A parcel that is only partially defined or that is missing a sequence of one or more lines that would otherwise close the parcel back … Read more

[ESRI software] The isolation level in an RDBMS specifying the minimum isolation from concurrent transactions. The transaction can read data that has been changed by concurrent transactions even before the … Read more

[data capture] A line that falls short of another line that it should intersect.

[map projections] A surface, such as the earth’s, that cannot be flattened into a map without stretching, tearing, or squeezing it. To produce a flat map of the round earth, … Read more

[network analysis] A network state in which each edge may or may not have an associated direction of flow. In an undirected network flow, the resource that traverses a network’s … Read more

[ESRI software] In Survey Analyst for field measurements, one of two types of lists in the List page. The uniform list has rows that represent survey objects of the same … Read more

[ESRI software] A condition that occurs in a network when an edge feature is not connected through the network to sources and sinks or if the edge feature is only … Read more

[analysisgeoprocessing] A topological overlay of two or more polygon spatial datasets that preserves the features that fall within the spatial extent of either input dataset; that is, all features from … Read more

[ESRI software] A DBMS-defined restriction specifying that each value stored in a column must be unique and that no other row can contain the same value.

[standards] A standard quantity used for measurements such as length, area, and height.

[statistics] Any statistical method for evaluating a single variable, rather than the relationship between two or more variables.

[statistics] A function for a single variable that gives the probabilities that the variable will take a given value.

A kriging method often used on data with a significant spatial trend, such as a sloping surface. In universal kriging, the expected values of the sampled points are modeled as … Read more

[coordinate systems] A projected coordinate system that covers all regions not included in the UTM coordinate system; that is, regions above 84 degrees north and below 80 degrees south. Its … Read more

An erosion model developed by the Agricultural Research Service of the United States Department of Agriculture that computes average annual soil loss caused by rainfall and associated overland flow. Factors … Read more

[astronomy] A timekeeping system that defines local time throughout the world by relating it to time at the prime meridian. Universal time is based on the average speed at which … Read more

[data models] In coverages, the first record in a polygon attribute table, representing the area beyond the outer boundary of the coverage.

[astronomy] The number of seconds, in coordinated universal time format, since January 1, 1970 (the start of the UNIX system).

[ESRI software] In Survey Analyst – Cadastral Editor, a parcel that has not been connected to the cadastral fabric, and that has its own local coordinate system.

[ESRI software] In Survey Analyst for field measurements, previously uncoordinated points.

[data structures] A raster catalog in which the raster datasets are not copied or altered by the geodatabase and there will only be a pointer connecting the raster catalog row … Read more

[ESRI software] In ArcGIS, the programming object that holds updates in a delta file.

[network analysis] In network tracing, the direction along a line or edge that opposes the direction of flow.

[geography] The field of geography concerning the spatial and cultural patterns and processes of cities and neighborhoods.

[Internet] Acronym for uniform resource locator. A standard format for the addresses of Web sites. A URL may look like this: http://www.esri.com. The first part of the address indicates what … Read more

The way in which statements in a command or programming language are actually used. In geoprocessing, usage for a tool or environment setting can be viewed at the command line.

[Internet] The amount of time between when a client gets a reference to a service and when they release it.

[software] The aspects of a computer system or program with which a software user can interact, and the commands and mechanisms used to control its operation and input data.

[programming] The identification used for authentication when a user logs in to a program.

[programming] In ArcObjects, a COM object that encapsulates a large number of fine-grained ArcObjects method calls and exposes a single coarse-grained method call. Utility COM objects are installed on a … Read more

Acronym for universal transverse Mercator. A projected coordinate system that divides the world into 60 north and south zones, 6 degrees wide.

[cartography] Acronym for Urban Vector Map. A vector-based data product in vector product format (VPF), typically at larger scales ranging from 1:2,000 to 1:25,000. UVMap data is typically collected over … Read more