GEOG 3315 - Module 4

Attribute

A record of a non-spatial characteristic that may or may not be related to geospatial features. Attributes are often rendered as tables and can be stored in simple text files or complex databases.

Ordinal Attribute

Ranks values in a specific order without determining the magnitude of the difference between them. Examples include ratings like high, medium, and low.

Nominal Attribute

Provides descriptive information without specifying order, size, or any quantitative information. Examples include colors, names, or driver’s license numbers.

Interval Attribute

Ranks both order and absolute difference (magnitude) with an arbitrary zero point. An example is temperature in degrees Fahrenheit.

Ratio Attribute

Similar to interval attributes but with a natural zero point, allowing for meaningful comparisons of magnitude. An example is age.

Data Type

A structure used to translate human-readable information into a format that a computer can store and process. Common data types include integer, float/real, text/string, and date.

Integer

A whole number that can be used for mathematical calculations, such as 1, 2458, or -54.

Float/Real

A decimal number used for mathematical calculations without rounding or truncation, such as 1.452 or -845.157.

Text/String

Contains characters, including letters and numbers, but cannot be used for mathematical calculations. Examples include 'GIS' or '125 Main St.'

Date

Holds time and date information, such as 12/10/2010, and can be used to calculate lengths of time between dates.

Attribute Query

Selects a subset of records based on values of specific attributes using set algebra operators and attribute values.

Set Algebra Operations

Operations used to determine whether two values are equivalent or not, including less than (

Boolean Algebra

Uses conditional operators like AND, OR, and NOT to evaluate values and assign outcomes, often used in attribute queries.

Geodatabase

A storage container for GIS data that can hold vector and raster data, enforce rules on input, and organize data efficiently.

Feature Dataset

A collection of feature classes within a geodatabase that must have the same coordinate system.

Feature Class

A collection of common features within a geodatabase, analogous to a single shapefile, with the same geometry.

Hierarchical Database

Organizes data into a tree-like structure with parent-child relationships, where each record is a row and each attribute is a column.

Relational Database

Uses a relational structure to collect data into tables that can be related to each other using intermediate tables, reducing duplication and database size.

Spatial Data Organization

Methods to keep data organized, such as using folders, copying files, deleting unnecessary items, and renaming files for easier recognition.

Query

A request for information from a database, often used to select specific records based on criteria.