GEOG 160
Mapping Our Changing World

4.7 Glossary


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.