Attribute: Data about a geographic feature often found in geographic databases and typically represented in the columns of the database.
Classification: Numerical data (at interval and ratio level) sorted into classes, typically defined as non-overlapping numerical data ranges.
Database: A collection of tables specifically designed for efficient retrieval and use.
Database Management System: Information systems that people use to store, update, and analyze non-geographic databases.
Difference: A data operation that produces a set of entities that appear in only one of two sets; thus it eliminates records that appear in both original sets.
Geographic Information Systems (GIS): A computer-based tool used to help people transform geographic data into geographic information.
Group: An attribute measurement level operation that combines data into fewer categories.
Information Systems: Computer-based tools that help people transform data into information.
Intersection: A data file that contains only records that are present in all files.
Interval Level Data: Numerical data with an arbitrary zero point on the measurement scale.
Isolate: The operation of selecting specific data and isolating it while setting other parts of the data aside.
Key: A common attribute among multiple databases/files that allow the database system to relate the separate files.
Level of Measurement: A systematic approach to data measurement for phenomena, as it cannot simply be counted.
Metadata: Data about data to document the content, quality, format, ownership, and lineage of individual data sets.
Nodes: Point locations specified by latitude and longitude coordinates.
Nominal Level Data: Data that are denoted with different names or categories.
Ordinal Level Data: The assignment of ranked or ordered observations to discrete categories.
Qualitative: A type of data that is based on a quality or characteristic.
Quantitative: A type of data that is based on quantities.
Query: A question or code addressed to the database for certain information.
Raster: Involves sampling attributes for a set of cells having a fixed size.
Ratio Level Data:Numerical data where the zero is not arbitrary on the measurement scale.
Records: Often rows in a database table, corresponding to individual entities.
Relational Database: Databases that contain numerous files that share one or more keys.
Relational Database Management Systems: Database systems that enable users to produce information from relational databases.
Spatial Queries: Questions addressed to a database, such as wanting to know a distance or the location where two objects intersect.
Standard Query Languages: A programming language used in database management systems.
Table: Data arranged in tabular form.
Union: A single file that includes all records and attributes for features that appear in one file or the other, with records in common merged to avoid repetition.
Vector: Involves sampling either specific point locations, point intervals along the length of linear entities, or points surrounding the perimeter of areal entities, resulting in point, line, and polygon features.