GIS Glossary/R

GIS Glossary

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radar
Acronym for radio detection and ranging. A device or system that detects surface features on the earth by bouncing radio waves off them and measuring the energy reflected back.

radar altimeter
An instrument that determines elevation, usually from mean sea level, by measuring the amount of time an electromagnetic pulse takes to travel from an aircraft to the ground and back again.

radar interferometry
The analysis of interferograms that have been created by IFSAR, or artificially. Radar interferometry involves the comparison of two or more images of the same area taken from different positions and calibrated with surveyed ground points to generate three-dimensional digital elevation models (DEMs), or models demonstrating slight movements of surface features.

radial basis functions
In ArcGIS Geostatistical Analyst, a deterministic interpolation method. The interpolated surface is forced to conform to the sample data points, and the method does not have standard errors associated with it. Spline interpolation is a special case of radial basis functions.

radian
The angle subtended by an arc of a circle that is the same length as the radius of the circle, approximately 57 degrees, 17 minutes, and 44.6 seconds. There are 2&#960; radians in one complete rotation.

radiation
The emission and propagation of energy through space in the form of waves. Electromagnetic energy and sound are examples of radiation.

radiometer
An instrument that measures the intensity of radiation in a particular band of wavelengths in the electromagnetic spectrum, such as infrared or microwave.

radiometric correction
Procedures that correct or calibrate aberrations in data values due to specific distortions from such things as atmosphere effects (such as haze) or instrumentation errors (such as striping) in remotely sensed data.

radiometric resolution
The sensitivity of a sensor to incoming reflectance. Radiometric resolution refers to the number of divisions of bit depth (for example, 255 for 8-bit, 65,536 for 16-bit, and so on) in data collected by a sensor.

radius
The distance from the center to a point on the outer edge of a circle, circular curve, or sphere.

random noise
In a spatial model, variation in the value of a variable that cannot be described by a mathematical function and is not spatially correlated: it includes measurement error and microscale variation (variation at a finer scale than that at which the data has been sampled). Random noise is one of the three main components&#8212;along with drift and spatially correlated variation&#8212;that contribute to the change in value of a variable over a surface. In a semivariogram, random noise is represented by the nugget. Random noise is sometimes called white noise.

range
A parameter of a variogram or semivariogram model that represents a distance beyond which there is little or no autocorrelation among variables.

range domain
A type of attribute domain that defines the range of permissible values for a numeric attribute. For example, the permissible range of values for a pipe diameter could be between 1 and 32 inches.

rank
A method of assigning an accuracy value to feature classes to avoid having vertices from a feature class collected with a high level of accuracy being snapped to vertices from a less accurate feature class. Vertices from higher ranking feature classes will not be moved when snapping with vertices with lower ranked feature classes. The highest rank is one; up to 50 different ranks can be assigned.

raster
A spatial data model that defines space as an array of equally sized cells arranged in rows and columns, and composed of single or multiple bands. Each cell contains an attribute value and location coordinates. Unlike a vector structure, which stores coordinates explicitly, raster coordinates are contained in the ordering of the matrix. Groups of cells that share the same value represent the same type of geographic feature.

raster band
One layer in a raster dataset that represents data values for a specific range in the electromagnetic spectrum (such as ultraviolet, blue, green, red, and infrared), or radar, or other values derived by manipulating the original image bands. A raster dataset can contain more than one band. For example, satellite imagery commonly has multiple bands representing different wavelengths of energy from along the electromagnetic spectrum.

Raster Calculator
An ArcGIS Spatial Analyst tool for performing mathematical calculations with operators and functions, setting up selection queries, or typing Map Algebra syntax. Inputs to the Raster Calculator can be raster datasets, raster layers, coverages, shapefiles, tables, constants and numbers.

raster catalog
A collection of raster datasets defined in a table of any format, in which the records define the individual raster datasets that are included in the catalog. Raster catalogs can be used to display adjacent or overlapping raster datasets without having to mosaic them together into one large file. In ArcView 3.x, raster catalogs were called image catalogs.

raster cell
The smallest unit of information in raster data, usually square in shape. In a map or GIS dataset, each cell represents a portion of the earth, such as a square meter or square mile, and usually has an attribute value associated with it, such as soil type or vegetation class.

raster cleanup
The process of drawing, filling, and erasing raster cells using ArcScan Raster Cleanup and Raster Painting tools.

raster data model
A representation of the world as a surface divided into a regular grid of cells. Raster models are useful for storing data that varies continuously, as in an aerial photograph, a satellite image, a surface of chemical concentrations, or an elevation surface.

raster dataset
In ArcGIS, a raster spatial data model that is stored on disk or in a geodatabase. Raster datasets can be stored in many formats, including TIFF, Imagine, ESRI Grid, and MrSid.

raster dataset band
One layer in a raster dataset that represents data values for a specific range in the electromagnetic spectrum (such as ultraviolet, blue, green, red, and infrared), or radar, or other values derived by manipulating the original image bands. A raster dataset can contain more than one band. For example, satellite imagery commonly has multiple bands representing different wavelengths of energy from along the electromagnetic spectrum.

raster intersection
Three or more lines in a raster that meet at a common point.

raster layer
In ArcGIS, a layer that references a raster as its data source and a raster renderer that defines how the raster data should be rendered and any additional display properties.

raster model
A representation of the world as a surface divided into a regular grid of cells. Raster models are useful for storing data that varies continuously, as in an aerial photograph, a satellite image, a surface of chemical concentrations, or an elevation surface.

raster postprocessing
In ArcScan, the automatic correction of vector feature results immediately after batch vectorization is completed. Postprocessing involves generalizing lines, straightening angles, and smoothing lines.

raster preprocessing
Simple raster editing that prepares images for viewing and analysis. Preprocessing includes georeferencing, clipping, positioning, resizing, enhancing, and mosaicking.

raster process definition file
In ArcGIS Image Server, an XML file that contains properties of the raster dataset, including metadata, as well as the definition of processes to be applied to one or more individual rasters. A raster process definition file has a .RPDef extension.

Raster Product Format
A data format composed of rectangular pixel arrays (compressed or uncompressed), produced by the National Geospatial-Intelligence Agency and U.S. allies for military applications.

raster snapping
An automatic editing operation in which points or features within a specified distance (tolerance) of other points or features are moved to match or coincide exactly with each others' coordinates.

raster statistics
Statistics that are calculated from the cell values of each band in a raster. The statistics that are calculated include the minimum, maximum, mean, and standard deviation cell values, and if the dataset is thematic, the number of classes. Statistics are required for some rendering and geoprocessing operations.

raster tile
An internal subsetting of a spatial dataset (commonly raster) into a manageable rectangular set, or rows and columns of pixels, typically used to process or analyze a large raster dataset without consuming vast quantities of computer memory.

raster tracing
An interactive vectorization process that involves drawing along the boundary of contiguous raster cells to create vector features.

rasterization
The conversion of points, lines, and polygons into cell data.

rasterized feature layer
A feature layer in ArcGlobe that exists as points, lines and polygons but is rendered as cell data. When layers are added to ArcGlobe, they may automatically be rendered in raster format to retain their cartographic symbology.

ratioing
In digital image processing, enhancing the contrast between features in an image by dividing the values of pixels in one image by the values of corresponding pixels in a second image.

ray tracing
A technique that traces imaginary rays of light from a viewer's eye to the objects in a three-dimensional scene to determine which parts of the scene should be displayed from that perspective.

RDBMS
Acronym for relational database management system. A type of database in which data is organized across one or more tables. Tables are associated with each other through common fields called keys. In contrast to other database structures, an RDBMS requires few assumptions about how data is related or how it will be extracted from the database.

real-time data
Data that is displayed immediately, as it is collected. Real-time data is often used for navigation or tracking.

real-time mode
The time mode in ArcGIS Tracking Analyst in which data is automatically displayed on the map after being added.

reclassification
The process of taking input cell values and replacing them with new output cell values. Reclassification is often used to simplify or change the interpretation of raster data by changing a single value to a new value, or grouping ranges of values into single values&#8212;for example, assigning a value of 1 to cells that have values of 1 to 50, 2 to cells that range from 51 to 100, and so on.

reconcile
In concurrency management, to merge all modified data in the current database edit session with a second version of the data.

record
A set of related data fields, often a row in a database, containing all the attribute values for a single feature. For example, in an address database, the fields that together provide the address for a specific individual comprise one record. In the SQL query language, a record is analogous to a tuple.

rectangular survey
The description of the location of land in the United States using a survey system established by the federal government in 1785. The system is based on the concept of a township, a square parcel of land measuring 6 miles on each side. The township's position is described as a number of 6-mile units east of a north–south line (called the meridian) and north or south of an east–west line (called the baseline). Each township is divided into 36 sections, each of which is 1 square mile. A section is divided into quarters equal to 160 acres. The quarter section may be further divided into four 40-acre parcels. Also referred to as the Public Land Survey System (PLSS).

rectification
The process of applying a mathematical transformation to an image so that the result is a planimetric image.

rectilinear
Characterized by straight lines, usually parallel to orthogonal axes.

recycling
The process by which server instances in a pool are replaced by new instances of services. Recycling allows services that have become unusable to be destroyed and replaced with fresh services, and it reclaims resources taken up by stale services.

redistricting
The process of revising the boundaries of administrative, legislative, or election districts.

redundancy
In Survey Analyst, occurs when the number of observed measurements is greater than the number of computed coordinates in a measurement network.

reference
A pointer to an object, interface, or other item allocated in memory. COM objects keep a running total of the references to themselves via the IUnknown interface methods AddRef and Release.

reference data
In geocoding, material containing the location and address information of specific features. Reference data consists of the spatial representation of the data and the related attribute table.

reference data source
In ArcGIS, a spatial data layer that a geocoding service uses to perform address geocoding. A reference data source can be any point, line, or polygon feature class that contains the necessary address attributes. Each address component is stored as a separate attribute. The address attributes can be contained in the reference data source itself or in a table joined to it.

reference datum
Any datum, plane, or surface from which other quantities are measured.

reference ellipsoid
An ellipsoid associated with a geodetic reference system or geodetic datum.

reference grid
A grid of numbered rows and lettered columns (or vice versa) superimposed on a map, used to find and identify features. Alphanumeric grids are commonly used as a reference system on local street maps.

reference level
A surface to which heights, elevations, or depths are referenced.

reference map
A map designed to show where geographic features are in relation to each other.

reference point
In Survey Analyst, a point with known coordinates, used as input to a computation.

reference scale
The scale at which symbols appear on a digital page at their true size, specified in page units. As the extent is changed, text and symbols will change scale along with the display. Without a reference scale, symbols will look the same at all map scales.

reference spheroid
An ellipsoid associated with a geodetic reference system or geodetic datum.

reference system
A method for identifying positions on the globe. This is often constructed with a grid that either refers to the earth's latitude and longitude (graticule), or a planar equivalent that divides grid lines by a fixed length from a predefined point of origin.

reference theme
In ArcView 3.x, a theme used to perform geocoding. A reference theme can be any point, line, or polygon theme that contains the necessary address fields. Each address component (such as street name, address range, street prefix, and street type) is stored as a separate field. The address fields can be contained in the reference theme itself or in a table joined to it. During geocoding, each address is matched to a feature in the reference theme that has matching address components (either the single address or address range), then coordinates for the new point features are determined.

referencing
In Survey Analyst, occurs when a copy of a coordinate from a different project is added to the survey point for exclusive use in your project. When this referencing happens, you must choose one of the following coordinates: the GIS coordinate or the current coordinate of the owning survey project.

referential constraint
A DBMS-defined restriction that ensures that foreign key values in the rows in the child table always have matching primary key values in the parent table.

referential integrity
A mechanism for ensuring that data remains accurate and consistent as a database changes. When changes are made to a table related to another table by a common key, the changes are automatically reflected in both tables.

reflectance
The proportion of incident radiant energy that is reflected by a surface. Reflectance varies according to the wavelengths of the incident radiant energy and the color and composition of the surface.

Regedit
A utility, part of the Windows operating system, that allows you to view and edit the system registry.

region
In geography, an area usually distinguished by common cultural or physical characteristics, such as Southern California, Western Europe, or Southeast Asia.

register
To align two or more maps or images so that equivalent geographic coordinates coincide.

registration
The step in the install process during which users are required to contact ESRI Customer Service and notify them of their single use, server, or developer product registration number.

registration number
A three-letter, nine-digit number (ABC123456789, for example) that authenticates software with ESRI. Every single use and server product, including their extensions or options, has a unique registration number.

registry
Stores information about system configuration for a Windows machine. COM uses the registry extensively, storing details of COM components including ProgIDs and ClassIDs, file location of the binary code, marshalling information, and categories in which they participate.

registry file
A file containing information in Windows Registry format. Double-clicking a .reg file in Windows will enter the information in the file into the system registry. Often used to register components to component categories.

regression
A statistical method for evaluating the relationship between a single dependent variable and one or more independent variables thought to influence the dependent variable. Regression is used to predict the value of the dependent variable or to determine whether an independent variable in fact influences the dependent variable, and to what extent.

regression coefficient
A value associated with each independent variable in a regression equation, representing the strength and type of relationship the independent variable has to the dependent variable. For example, fire frequency might be modeled as a function of solar radiation, vegetation, precipitation, and aspect. A positive relationship between fire frequency and solar radiation is likely (the more sun, the more frequent the fire incidents). When the relationship is positive, the sign for the associated coefficient is also positive. A negative relationship between fire frequency and precipitation is also likely (places with more rain have fewer fires). Coefficients for negative relationships have negative signs. If the relationship is strong, the absolute value of the coefficient is large. Weak relationships are associated with coefficients near zero.

regression equation
The mathematical formula applied to independent variables to best predict the dependent variable being modeled. The notation in regression equations is always Y for the dependent variable and X for the independent variables. Each independent variable is associated with a regression coefficient describing the strength and sign of that variable's relationship to the dependent variable. A regression equation might look like this (where b represents a regression coefficient): Y = b0 + b1X1</SUBSCRIPT> + b</I>2</SUBSCRIPT>X</I>2</SUBSCRIPT> + &#8230;b</I>n</SUBSCRIPT>X</I>n

RegSvr32
A Windows utility that registers a DLL or similar component library to a system registry. A DLL and its components must be registered before it can be used.

rehydrate
In programming, to reinstantiate an object and its state from persisted storage.

reject processing
Handling unmatched addresses through fine-tuning the geocoding process. After a table of addresses are matched the first time, unmatched addresses can be reviewed or edited. Reject processing attempts to find possible matches by correcting errors or adjusting search criteria for the addresses that fail the first time.

relate
An operation that establishes a temporary connection between records in two tables using a key common to both.

relate manager
An ArcToolbox utility used to build, modify, save, and delete connections (relates) between tables. Saved connections can be reactivated in future ArcToolbox sessions.

relational database
A data structure in which collections of tables are logically associated with each other by shared fields.

relational database management system
A type of database in which data is organized across one or more tables. Tables are associated with each other through common fields called keys. In contrast to other database structures, an RDBMS requires few assumptions about how data is related or how it will be extracted from the database.

relational join
Appending the fields of one table to those of another through an attribute or field common to both tables. A join is usually used to attach more attributes to the attribute table of a geographic layer.

relational operator
In ArcGIS Spatial Analyst, an operator that evaluates specific relational conditions. If a condition is TRUE, the output is assigned a value of 1. If the condition is FALSE, the output is assigned a value of 0.

relationship
An association or link between two objects in a database. Relationships can exist between spatial objects (features), between nonspatial objects (rows in a table), or between spatial and nonspatial objects.

relationship class
An item in the geodatabase that stores information about a relationship. A relationship class is visible as an item in the ArcCatalog tree or contents view.

relative accuracy
A measure of positional consistency between a data point and other, near data points. Relative accuracy compares the scaled distance of objects on a map with the same measured distance on the ground.

ring
A bearing measured relative to a vessel or aircraft's heading.

relative coordinates
Coordinates identifying the position of a point with respect to another point.

relative mode
A way of using a digitizing tablet in which the digitizer puck behaves like a mouse; the puck is used to point to interface elements rather than to trace shapes on the surface of the digitizing tablet.

relative path
In computing, the location of a computer file given in relation to the current working directory.

relative replica
In geodatabase editing, the other replica in a replica pair of parent and child. The relative replica to a child replica is the parent replica, and vice versa.

reliability diagram
A map element that contains a simplified view of the sources used to compile a map.

relief
Elevations and depressions of the earth's surface, including those of the ocean floor. Relief can be represented on maps by contours, shading, hypsometric tints, digital terrain modeling, or spot elevations.

relief shading
Shadows drawn on a map to simulate the effect of the sun's rays over the varied terrain of the land.

rematching
The process of regeocoding a feature or features in a geocoded feature class.

remote sensing
Collecting and interpreting information about the environment and the surface of the earth from a distance, primarily by sensing radiation that is naturally emitted or reflected by the earth's surface or from the atmosphere, or by sensing signals transmitted from a device and reflected back to it. Examples of remote-sensing methods include aerial photography, radar, and satellite imaging.

remote-sensing imagery
Imagery acquired from satellites and aircraft, including panchromatic, radar, microwave, and multispectral satellite imagery.

renderer
A mechanism that defines how data appears when displayed. For example, the hillshade renderer for raster data in ArcMap calculates and applies shading based on existing data values for slope and aspect.

ring
The process of drawing to a display; the conversion of the geometry, coloring, texturing, lighting, and other characteristics of an object into a display image.

Rendering tab
In 3D Analyst, a tab on the Layer Properties dialog box that allows users to control whether or not a layer is displayed during scene navigation, how it is shaded, and its drawing priority. It also allows users to adjust how the computer's memory is allocated when rendering large images.

repeatable read
The isolation level in a database management system (DBMS) that ensures that when the same rows are read multiple times during the course of a transaction, the returned values are the same between subsequent reads.

replica
In geodatabase editing, the portion of the data in a geodatabase that is copied from a source geodatabase to a destination geodatabase during the replication process. The replica includes information needed to synchronize changes to the data. There are three types of replicas: one-way replicas, two-way replicas, and check-in/checkout replicas.

replica geodatabase
In geodatabase editing, the portion of the data in a geodatabase that is copied from a source geodatabase to a destination geodatabase during the replication process. The replica includes information needed to synchronize changes to the data. There are three types of replicas: one-way replicas, two-way replicas, and check-in/checkout replicas.

replica pair
In geodatabase editing, each combination child and parent replica.

replica schema changes file
An XML file that describes schema differences between the data in a replica and its relative replica.

replica schema file
A workspace document file that describes the schema of the data in a replica.

replica version
In geodatabase editing, the version being replicated during the replication process. For all replica types, the replica version for a parent replica is the version the user was connected to when the replica was created. For one-way and two-way replicas, the replica version for a child replica is always the default version. Changes made to replica versions may be synchronized between the replicas.

replication
A means of copying and distributing data from one database to local, remote, or mobile users and then synchronizing between these databases for consistency.

Report Web Service
A SOAP ArcWeb service for creating a report or a map for a specified area in the United States. For a given study area or trade area, the Report Web Service applies a spatial query (if needed), obtains the necessary raw data for the report, aggregates it, and returns the aggregated results in PDF, Excel, or XML format.

repository
In ArcGIS, a database that contains the schema information needed to create a geodatabase from a UML model created using a CASE tool.

representation
A method of illustrating data so it can be viewed and understood. In cartography, representation is used to depict likenesses of real-world features in such a way that the depictions symbolize or correspond to the real features. Representation is used to present information in a format that is viewable, storable, and transferable.

representation control point
In ArcGIS, a specialized geometry vertex that controls the phases of certain geometric effects in a representation rule.

representation rule
In ArcGIS, the combination of symbology and any geometric effects that together define the appearance of features sharing a common representation rule ID.

representative fraction
The ratio of a distance on a map to the equivalent distance measured in the same units on the ground. A scale of 1:50,000 means that one inch on the map equals 50,000 inches on the ground.

resampling
The process of interpolating new cell values when transforming rasters to a new coordinate space or cell size.

residual
In a regression model, the difference between the observed Y value and the predicted Y value; the unexplained portion of the dependent variable. Predicted values rarely match observed values exactly. The residual is one measure of model fit. Large residuals indicate poor model fit.

resolution
The detail with which a map depicts the location and shape of geographic features. The larger the map scale, the higher the possible resolution. As scale decreases, resolution diminishes and feature boundaries must be smoothed, simplified, or not shown at all; for example, small areas may have to be represented as points.

resolution merging
Sharpening a low-resolution multiband image by merging it with a high-resolution panchromatic image.

resource center
ESRI Web site providing various online resources&#8212;such as online help, user forums, blogs, samples, user communities, developer content, and so on&#8212;to help users learn about and use a particular ESRI product. The Resource Center gateway is located at <A HREF="http://resources.esri.com" TARGET="_blank">http://resources.esri.com</A>.

REST
Acronym for Representational State Transfer</I>. An architecture for exchanging information between peers in a decentralized, distributed environment. REST allows programs on different computers to communicate independently of an operating system or platform by sending a Hypertext Transfer Protocol (HTTP) request to a uniform resource locator (URL) and getting back data in some format&#8212;for example, XML, or inside a URL. REST is used in Web services.

restriction
A Boolean network element attribute used for limiting traversal through a network dataset. "One way street," "no trucks allowed," and "buses only" are examples of restrictions.

reverse geocoding
The process of finding a street address from a point on a map.

RF
The ratio of a distance on a map to the equivalent distance measured in the same units on the ground. A scale of 1:50,000 means that one inch on the map equals 50,000 inches on the ground.

RGB
A color model that uses red, green, and blue, the primary additive colors used to display images on a monitor. RGB colors are produced by emitting light, rather than by absorbing it as is the case with ink on paper. Adding 100 percent of all three colors results in white.

rhumb line
A complex curve on the earth's surface that crosses every meridian at the same oblique angle. A rhumb line path follows a single compass bearing; it is a straight line on a Mercator projection, or a logarithmic spiral on a polar projection. A rhumb line is not the shortest distance between two points on a sphere.

rich client application
An application that stores and retrieves data locally rather than remotely, enabling easy interaction with other internal resources. Client-side applications maintain a consistent look and feel and support a complex user interface but do not offer the security of server-side applications.

ring
In ArcGIS, a geometric element from which polygons are constructed. A ring is a closed path (one that begins and ends at the same point).

ring study
The simplest and most widely used type of market-area analysis, in which a circle is generated around an area on a map; then the underlying demographics are extracted from the area delineated by the circle. Generally, a ring study is used to generate a rough visualization of the market area around a point.

river addressing
In hydrology applications, another name for linear referencing. River addressing allows objects such as gauging stations to be located by their relative positions along a line feature.

RMS error
Acronym for root mean square error</I>. A measure of the difference between locations that are known and locations that have been interpolated or digitized. RMS error is derived by squaring the differences between known and unknown points, adding those together, dividing that by the number of test points, and then taking the square root of that result.

RMSE
Acronym for root mean square error</I>. A measure of the difference between locations that are known and locations that have been interpolated or digitized. RMS error is derived by squaring the differences between known and unknown points, adding those together, dividing that by the number of test points, and then taking the square root of that result.

roamer
A transparent gauge that represents easting and northing distances at a given map scale, used to locate positions on a map.

roller-feed scanner
A type of scanner that moves a document through a roller assembly over camera sensors that capture a digital image.

root mean square error
A measure of the difference between locations that are known and locations that have been interpolated or digitized. RMS error is derived by squaring the differences between known and unknown points, adding those together, dividing that by the number of test points, and then taking the square root of that result.

route
Any line feature, such as a street, highway, river, or pipe, that has a unique identifier.

route analysis
In ArcGIS Network Analyst, a type of network analysis that determines the best route from one network location to one or more other locations. It can also calculate the quickest or shortest route depending on the impedance chosen. The order of the stops may be determined by the user. For example, if the impedance is time, then the best route is the quickest route.

Route Editing toolbar
A set of tools that allows users to create and modify routes in ArcMap.

route event
In linear referencing, linear, continuous or point features occurring along a base route system.

route event source
In linear referencing, the result of the dynamic segmentation process. A route event source serves an event table as a dynamic feature class. Every row in the table is served as a feature whose shape is calculated when needed. For example, a route event source can act as the basis of a feature layer in ArcMap.

route event table
In linear referencing, a table that stores route locations and their attributes. A route event table, at a minimum, consists of a route identifier field and a measure location field (point events) or fields (line events).

route feature class
In linear referencing, a collection of routes with a common system of measurement stored in a single feature class (for example, a set of all highways in a county).

Route Finder Web Service
A SOAP ArcWeb service for generating multipoint driving directions between locations. This Web service accepts x,y coordinate inputs for two or more locations, along with routing preferences, and returns a route map and textual driving directions for the suggested route.

route identifier
In linear referencing, a numeric or character value used to identify a route.

route location
In linear referencing, a discrete location along a route (point) or a portion of a route (line). A point route location uses only a single measure value to describe a discrete location along a route. A line route location uses both a from- and to-measure value to describe a portion of a route.

route measure
In linear referencing, a value stored along a linear feature that represents a location relative to the beginning of the feature, or some point along it, rather than as an x,y coordinate. Measures are used to map events such as distance, time, or addresses along line features.

route measure anomalies
In linear referencing, route measure values that do not adhere to the expected behavior. Route measure anomalies can often be fixed with ArcMap route editing tools.

route reference
In linear referencing, a collection of routes with a common system of measurement stored in a single feature class (for example, a set of all highways in a county).

route renewal
In ArcGIS Network Analyst, an object used in vehicle routing problem (VRP) analysis. A route renewal object specifies a depot that can be used by a particular route to load/unload the vehicle along the route as necessary so that the capacity is reset and the route can service more orders.

route seed point
In ArcGIS Network Analyst, a feature used in vehicle routing problem (VRP) analysis. A route seed point can be used to cluster the orders for a specified route.

route server
A public ArcIMS virtual server that supports routing, reverse geocoding, and geocoding of Spatial Data Compressed (SDC) data. This server is available as an extension to ArcIMS.

route service
A type of Web service that determines driving directions between a set of route stops.

route zone
In ArcGIS Network Analyst, a feature used in vehicle routing problem (VRP) analysis. A route zone has a polygon geometry and can be used to define the area of coverage or available service for a specified route.

rover
A portable GPS receiver used to collect data in the field. The rover's position can be computed relative to a second, stationary GPS receiver.

roving window
On a raster, an analysis boundary or processing window within which cell values affect calculations and outside which they do not. Filters are used mainly in cell-based analysis where the value of a center cell is changed to the mean, the sum, or some other function of all cell values inside the filter. A filter moves systematically across a raster until each cell has been processed. Filters can be of various shapes and sizes, but are most commonly three-cell by three-cell squares.

row
A record in a table.

row standardization
A technique for adjusting the weights in a spatial weights matrix. When weights are row standardized, each weight is divided by its row sum. The row sum is the sum of weights for a feature&#8217;s neighbors.

RPF
Acronym for Raster Product Format</I>. A data format composed of rectangular pixel arrays (compressed or uncompressed), produced by the National Geospatial-Intelligence Agency and U.S. allies for military applications.

R-squared
A statistic computed by the regression equation to quantify model performance. The value of R-squared ranges from 0 to 100 percent. If a model fits the observed dependent variable values perfectly, the R-squared value is 1.0, although this is highly unlikely. An R-squared value like 0.49, for example, is far more likely, and means that the model explains 49% of the variation in the dependent variable.

RSS
Acronym for Really Simple Syndication</I>, Resource Description Framework (RDF) Site Summary</I>, or Rich Site Summary</I>, depending on the source. A simple, structured XML format for sharing content among different Web sites. RSS documents include key metadata elements such as author, date, title, a brief description, and a hypertext link. This information helps a user (or an RSS publisher service) decide what materials are worth further investigation. Examples include news feeds, events lists, news stories, headlines, and excerpts from blogs and discussion forums.

RSS feed
A text, audio, or media clip delivered over the Internet using RSS technology. RSS feeds can be delivered on demand to a browser with RSS-enabled software.

R-tree
A tree data structure, similar to a B-tree, used for indexing spatial data within a database. In an R-tree structure, data is sorted into a set of hierarchical nodes that may overlap. Each node has a variable number of entries, each of which includes an identifier for child nodes or actual data elements and a bounding box for all entries within the child node or the data elements. Searching algorithms check the bounding boxes before searching within a child node, thus avoiding extensive searches.

rubber banding
A procedure for adjusting the coordinates of all the data points in a dataset to allow a more accurate match between known locations and a few data points within the dataset. Rubber sheeting preserves the interconnectivity between points and objects through stretching, shrinking, or reorienting their interconnecting lines.

rubber sheeting
A procedure for adjusting the coordinates of all the data points in a dataset to allow a more accurate match between known locations and a few data points within the dataset. Rubber sheeting preserves the interconnectivity between points and objects through stretching, shrinking, or reorienting their interconnecting lines.

run time
The time during which a program is running, or the time it takes to run a program.

run-length encoding
A data compression technique for storing raster data. Run-length encoding stores data by row. If two or more adjacent cells in a row have the same value, the database stores that value once instead of recording a separate value for each cell. The more adjacent cells there are with the same value, the greater the compression.

runtime environment
The host that provides the services required for compiled code to execute. The Service Control Manager (SCM) is effectively the runtime environment for COM. The Visual Basic Virtual Machine (VBVM) is the runtime environment that runs Visual Basic code.