Oracle7 Spatial Data Option User's Guide and Reference

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Glossary

area An extent or region of dimensional space.

attribute Descriptive information characterizing a geographical feature such as a point, line, or area.

attribute data Non-dimensional data which provides additional descriptive information about multidimensional data, for example a class or feature such as a bridge or a road.

boundary

1. The lower or upper extent of the range of a dimension, expressed by a numeric value.

2. The line representing the outline of a polygon.

contains A geometric relationship where one object completely encompasses another and the inner object does not touch any boundaries of the outer. The outer object contains the inner object. See also inside.

coordinate system A reference system for the unique definition for the location of a point in n-dimensional space.

coordinates An n-tuple of values uniquely defining a point in an n-dimensional coordinate system.

covers A geometric relationship in which one object encompasses another and the inner object touches the boundary of the outer object in one or more places.

data dictionary A repository of information about data. A data dictionary stores relational information on all of the objects in a database.

decompose To separate or resolve into constituent parts or elements, or into simpler compounds.

dimensional data Data that has one or more dimensional components and is described by multiple values.

disjoint A geometric relationship where two objects do not interact in any way. Two disjoint objects do not share any element or piece of their geometry.

equal A geometric relationship in which two objects are considered to represent the same geometric figure. The two objects must be composed of the same number of points, however, the ordering of the points defining the two objects' geometries may differ (clockwise or counter-clockwise.)

extent A rectangle bounding a map, the size of which is determined by the minimum and maximum map coordinates.

feature An object in a spatial database with a distinct set of characteristics.

grid A data structure composed of points located at the nodes of an imaginary grid. The spacing of the nodes is constant in both the horizontal and vertical directions.

geographically referenced data See spatiotemporal data.

georeferenced data See spatiotemporal data.

geographical information system A computerized database management system used for the capture, conversion, storage, retrieval, analysis, and display of spatial data. GIS See geographical information system.

HHCODE A datatype representing the intersection point of multiple dimensions. It encodes these multiple dimensions into a unique, linear value. The HHCODEs are used for both spatial indexing and partitioned point data.

high water mark Expressed in number of records and associated with the Spatial Data Option partitioned table structure, it defines the maximum number of records to store in a table before decomposing another level. The high water mark determines the maximum size of a partition within the Spatial Data Option table.

hole A polygon can include subelements which negate sections of its interior For example, consider a polygon representing a map of a buildable land with an inner polygon representing where a lake is located.

homogeneous Spatial data of one feature type such as points, lines, or regions.

hyperspatial data In mathematics, any space comprised of more than the three standard x, y, and z dimensions, also referred to as multidimensional data.

index Identifier that is not part of a database and used to access stored information.

inside A geometric relationship where one object is encompassed by a larger object and the inner object does not touch the boundary of the outer. The smaller object is inside the larger. See also contains.

key A field in a database used to obtain access to stored information.

keyword Synonym for reserved word.

latitude North/South position of a point on the Earth defined as the angle between the normal to the Earth's surface at that point and the plane of the equator.

line A geometric object represented by a series of points, or inferred as existing between two coordinate points.

longitude East/West position of a point on the Earth defined as the angle between the plane of a reference meridian and the plane of a meridian passing through an arbitrary point.

partition 1)The spatial table that contains data only for a unique bounded n-dimensional space. 2) The process of grouping data into partitions that maintain the dimensional organization of the data.

partition key column The primary HHCODE column which is used to dimensionally partition the data. One HHCODE datatype column must be identified as the partition key for the table to be registered as partitionable in the Spatial Data Option data dictionary. There can only be one partition key per spatial table. Note that this is only used for partitioned point data, and not spatially indexed data.

partitioned table The spatial logical table structure that contains one or more partitions. Use partitioned tables only if you are dealing with a very large amount of point data (over 50 GB.)

polygon A class of spatial objects having nonzero area and perimeter, and representing a closed boundary region of uniform characteristics.

proximity A measure of inter-object distance.

query A set of conditions or questions that form the basis for the retrieval of information from a database.

query window Area within which the retrieval of spatial information and related attributes is performed.

RDBMS See Relational Database Management System.

recursion A process, function, or routine that executes continuously until a specified condition is met.

region An extent or area of multidimensional space.

Relational Database Management System (RDBMS) A computer program designed to store and retrieve shared data. In a relational system, data is stored in tables consisting of one or more rows, each containing the same set of columns. Oracle is a relational database management system. Other types of database systems are called hierarchical or network database systems.

resolution The number of subdivision levels of data.

scale

• The number of digits to the right of the decimal point in a number representing the level of resolution of an HHCODE.

• The ratio of the distance on a map, photograph, or image to the corresponding image on the ground, all expressed in the same units.

SD*Loader A utility used with previous versions of the Spatial Data Option to load formatted data into spatial tables. Loading is now accomplished through the SQL*Loader.

spatial data Data that is referenced by its location in n-dimensional space. The position of spatial data is described by multiple values. See also hyperspatial data.

Spatial Data Option data dictionary An extension of the Oracle7 data dictionary. It keeps track of the number of partitions created in a spatial table. The Spatial Data Option data dictionary is owned by MDSYS.

SLF See Spatial Load Format.

sort The operation of arranging a set of items according to a key that determines the sequence and precedence of items.

spatial A generic term used to reference the mathematical concept of n-dimensional data.

spatial database A database containing information indexed by location.

spatial data model A model of how objects are located on a spatial context.

spatial data structures A class of data structures designed to store spatial information and facilitate its manipulation.

Spatial Load Format (SLF) The format used to load data into spatial tables in a previous version of the Spatial Data Option. Loading is now accomplished with the standard SQL*Loader.

spatial query A query that includes criteria for which selected features must meet location conditions.

spatiotemporal data Data that contains time and/or location components as one of its dimensions, also referred to as geographically referenced data or georeferenced data.

tiling The process of covering a geometry with rectangular "tiles" through tessellation.

touch A geometric relationship where two objects share a common point on their boundaries, but their interiors do not intersect.

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