Geographic Information Systems (GIS) Terminology Review

A comprehensive set of flashcards covering key terms and definitions related to Geographic Information Systems (GIS) as discussed in the lecture notes.

Geographic Information Systems (GIS)

A particular form of information system that holds spatially referenced data and attribute data used to analyze spatial relationships and model spatial processes.

Longitudinal data

Data that focuses on changes over time with fixed subjects or locations.

Cross-sectional data

Data focusing on spatial changes at fixed time, collected simultaneously at multiple locations.

Dyad

A pair of related but distinct objects or nodes linked by a connection or relationship.

Connectivity

The manner in which features in GIS are topologically linked.

Database

A collection of non-redundant data that can be shared by different application systems.

Metadata

Contextual information about a dataset, including details like date/time, origin, and data collectors.

Database Management System (DBMS)

Software that allows users to create, store, query, and manage databases.

Structured Query Language (SQL)

The standard language used to query information in relational databases.

Geoid

A model of Earth’s shape representing the mean sea level influenced by gravity.

Coordinate system

A framework for defining, representing, and measuring the spatial location of features on Earth's surface.

Euclidean distance

The shortest distance between two points on a plane in a straight line.

Great circle distance

The shortest distance between two points on the surface of a sphere, accounting for Earth’s curvature.

Affine transformation

A linear conversion of object coordinates from one Cartesian system to another, where parallel lines remain parallel.

Run Length Encoding (RLE)

A raster data compression technique that stores a sequence of identical cell values as a single value and count.

Raster

A data structure made up of a grid of cells, each representing a location on the Earth's surface.

Cell resolution

Refers to the area represented by a single raster cell, affecting the image detail's level.

Map algebra

Operations applied to one or more layers of raster data to produce an output layer.

Local raster operation

Operations that produce a new layer from other raster layers based on the same cell's values.

Focal raster operation

Produces a new layer from old raster layers by determining new cell values based on neighboring cell values.

Zonal raster operation

Aggregates cell values for each geographic zone that exhibits a particular quality.

Spatial filtering

Using a focal function to filter raster data, providing a weighted average of surrounding cell values.

Hierarchical data structure (HDS)

A way of organizing data from the top down, where each 'parent' node can have multiple 'children' nodes.

Quadtree

An approach to encoding raster data storage using repetitive division of space with quadrats.

Tesseral arithmetic

A math form that helps decode quadtree addressing schemes using binary addition.

Polyline

A shape made up of a series of connected segments.

Topology

Properties that remain unchanged when an object is distorted or stretched for vector data.

Planar enforcement

A method to clean up GIS data by ensuring no overlapping polygons.

Minimum enclosing (bounding) rectangle

The smallest rectangle that completely contains an object, aligned with the coordinate axes.

Polygon overlay

The process of combining two or more vector base layers to produce a new polygon layer.

Centroid

The geometric center of a spatial feature, calculated as the average of its vertices.

Vertex / node

The (x,y) coordinate that defines the shape or path of a polygon or network.

Edge / arc

The line that connects two points (vertices/nodes) creating a boundary or connectivity.

Graph

A data structure representing a network composed of nodes (vertices) and edges (arcs).

Network

A graph with numbers associated with its edges.

Shortest path

The most efficient route between two or more points in a network, identified using algorithms like Dijkstra.

Length

Measure of distance, time,  or proximity that serves as a spatial attribute of an object, location, or pair of objects (dyad) in GIS