R

Range Domains

A range domain is the span of numeric values between which an attribute value must fall.

Raster

A cellular data structure composed of rows and columns for storing images. Groups of cells with the same value represent features.

RDBMS

Relational database management system. A database management system with the ability to access data organized in tabular files that can be related to each other by a common field (item). An RDBMS has the capability to recombine the data items from different files, providing powerful tools for data usage.

Record

1. In an attribute table, a single 'row' of thematic descriptors. In SQL terms, a record is analogous to a tuple. 2. A logical unit of data in a file. For example, there is one record in the ARC file for each arc in a coverage.

Relate

An operation that establishes a temporary connection between corresponding records in two tables using an item common to both (i.e., relate key). Each record in one table is connected to those records in the other table that share the same value for the common item.

Relate Key

The common set of columns used to relate two attribute tables.

Relational Database

A method of structuring data as collections of tables that are logically associated to each other by shared attributes. Any data element can be found in a relation by knowing the name of the table, the attribute (column) name, and the value of the primary key.

Relationship Class

Objects in a real-world system often have particular associations with other objects in the database. These kinds of associations between objects in the geodatabase are called relationships. Relationships can exist between spatial objects (features in feature classes), between nonspatial objects (rows in a table), or between spatial and nonspatial objects. While spatial objects are stored in the geodatabase in feature classes, and nonspatial objects are stored in object classes, relationships are stored in relationship classes.

Resolution

1. Resolution is the accuracy at which a given map scale can depict the location and shape of geographic features. The larger the map scale, the higher the possible resolution. As map 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.

2. Distance between sample points in a lattice. 3. Size of the smallest feature that can be represented in a surface. 4. The number of points in x and y in a grid or lattice (e.g., the resolution of a U.S. Geological Survey one-degree DEM is 1201 x 1201 mesh points).

Role

Defines the capabilities a user is allowed within the process flow. For example, a user with the Approval Officer role, may view sessions and designs with a Pending Approval state and may transition them using the Approve and Reject transitions. Used interchangeably with User Role.

Rotation Algorithms

The style of rotation used to turn a point feature. Use ArcInfo's layer Properties dialog to determine a geographic or arithmetic algorithm. To access this dialog, right-click a layer, select Properties | Symbology tab | Advanced button.

Row

1. A record in an attribute table. The horizontal dimension of a table composed of a set of columns containing one data item each.

2. A horizontal group of cells in a grid, or pixels in an image.