GIS Dictionary

1 [data quality] The closeness of a repeated set of observations of the same quantity to one another. Precision is a measure of the control over random error. For example, … Read more

[spatial statistics use for geostatistics] In spatial modeling, the process of forming a statistic from observed data to assign values to random variables at locations where data has not been … Read more

[spatial statistics use for geostatistics] A value quantifying the uncertainty of a prediction; mathematically, the square-root of the prediction variance. (The prediction variance is the variation associated with the difference … Read more

[software] User-specified settings that determine how an application will act or appear when it is used.

[ESRI software] Used within the Survey Analyst Survey Explorer’s Point Identifier field to separate the prefix and point name strings.

[ESRI software] In coverages, refers to incomplete region topology. Region topology defines region-arc and region-polygon relationships. A topological region has both the region-arc relationship and the region-polygon relationship. A preliminary … Read more

[ESRI software] In ArcGlobe, a cache that is built prior to viewing, using an independent process accessed from the shortcut menu of a layer.

[ESRI software] A live view of GIS data in ArcCatalog. Users can pan and zoom the preview, query features, and create thumbnail images to store in metadata.

[graphics computing] Colors from which all other colors are derived in a particular color system. On a display monitor, these colors are red, green, and blue. In printing, they are … Read more

[database structures] An attribute or set of attributes in a database that uniquely identifies each record. A primary key allows no duplicate values and cannot be null.

[database structures] In geocoding, the attribute table associated with the primary reference data. Based on the address locator style selected, certain address elements must be present in the primary table.

[coordinate systems] In a coordinate system, any line of longitude designated as 0 degrees east and west, to which all other meridians are referenced. The Greenwich meridian is internationally recognized … Read more

In astronomy and geodesy, the vertical circle that passes through an observer’s zenith and through the east and west points of the horizon.

[ESRI software] An ArcIMS virtual server that offers functionality not directly accessible when creating a Web site. The functionality associated with each of the three private ArcIMS virtual servers (geocode … Read more

Usually a text file named prj.adf that is associated with a coverage, GRID, or TIN. The PRJ file contains the coordinate system information for the data. In a more general … Read more

[GPS] Acronym for pseudo-random noise code. A repeating radio signal broadcast by each GPS satellite and generated by each GPS receiver. In a given cycle, the satellite and the receiver … Read more

[statistics] A measure of the likelihood that a particular outcome, such as a spatial pattern or event, will occur given a set of possible outcomes. Probability values range from 0 … Read more

[statistics] A surface that gives the probability that the variable of interest is above or below a specified threshold value.

[programming] In software, a block of code that performs some task. Procedures are commonly used to organize code into reusable units. In object-oriented programming, a procedure that is specific to … Read more

1 [modeling] In geoprocessing in ArcGIS, a tool and its parameter values. One process, or multiple processes connected together, creates a model. 2 [ESRI software] In ArcGIS Image Server, applied … Read more

[ESRI software] In ArcGIS Image Server, a list of raster processes that are performed on the fly by the server on raster data. The full process chain contains the raster … Read more

[cartography] A graph of the elevation of a surface along a specified line.

[ESRI software] A string value, stored in the system registry, identifying a class by library and class name, for example esriCarto.FeatureLayer. The ProgID registry key also contains the human-readable name … Read more

1 [ESRI software] In Survey Analyst, a specific task for capturing survey data. This can include anything from a field control survey to data entry from a subdivision plan. 2 … Read more

[ESRI software] A geodatabase designed to manage database and map production for the Production Line Tool Set (PLTS). The PMC stores metadata and geometries of projects, products and source material.

[modeling] Any data in a process that existed before the process existed.

[ESRI software] In an ArcView 3.x project, the process of updating document paths when referenced document data is moved from one disk location to another. Project repair can be avoided … Read more

A reference system used to locate x, y, and z positions of point, line, and area features in two or three dimensions. A projected coordinate system is defined by a … Read more

A measurement of locations on the earth’s surface expressed in a two-dimensional system that locates features based on their distance from an origin (0,0) along two axes, a horizontal x-axis … Read more

[coordinate systems] A method by which the curved surface of the earth is portrayed on a flat surface. This generally requires a systematic mathematical transformation of the earth’s graticule of … Read more

[data conversion] The mathematical conversion of a map from one projected coordinate system to another, generally used to integrate maps from two or more projected coordinate systems into a GIS.

[data conversion] A transformation used only to transform coordinates digitized directly from high-altitude aerial photographs of relatively flat terrain, assuming there is no systematic distortion in the photographs.

[mathematics] An ellipsoid created by rotating an ellipse around its major axis.

[ESRI software] An attribute of an object defining one of its characteristics or an aspect of its behavior.

[ESRI software] A file that stores attributes for a particular ArcIMS item or function. Property files have a .properties file extension.

[software] A user interface component that provides access to change the properties of an object or objects.

[symbology] A symbol whose size differs in relation to the phenomenon being mapped.

[spatial analysis] A type of analysis in which geographic features (points, lines, polygons, or raster cells) are selected based on their distance from other features or cells.

[spatial analysis] A form of spatial query in which geographic features within a specified distance of a particular feature are selected.

[programming] A local representation of a remote object, supporting the same interfaces as the remote object. All interaction with the remote object from the local process is mediated via the … Read more