Introduction to Geographic Information Systems (GIS)

Vocabulary flashcards covering foundational concepts of Geographic Information Systems (GIS), cartography, spatial data models, map scales, projections, and geodatabases based on Lecture 1.

Geographic Information System (GIS)

A unified system composed of software, hardware, data, and methods designed to collect, store, analyze, and visualize information connected to a geographic location.

Burrough (1986) Definition of GIS

A process-oriented characterization defining GIS as an integrated chain of tools working together to collect, store, analyze, and display data linked to a specific location on Earth.

ESRI Definition of GIS

A utility-focused description defining GIS as both a mapping and analysis tool that enables businesses and public authorities to make well-informed decisions.

Jack Dangermond's Perspective on GIS

The viewpoint expressed by ESRI's founder that GIS is fundamentally about discovering meaning and insight in data by revealing spatial relationships and overlaps that cannot be seen with the naked eye.

Spatial Analysis

The core functional stage of GIS where real value is created by mathematically computing spatial relationships—such as distance, overlap, and proximity—to answer concrete questions like flood risk assessment or optimal facility siting.

Decision Pyramid (Grossmann, 1983)

A conceptual framework demonstrating how vast volumes of unstructured physical reality and raw geographic data at the base are progressively filtered, modeled, and transformed into concise insight and informed decisions at the top.

Geographic Information Equation

The foundational principle defined as $\text{DATA} + \text{LOCATION} = \text{GEOGRAPHIC INFORMATION}$, which allows distinct datasets to be mathematically compared through distance, direction, and spatial overlap.

GeoAI

The integration of artificial intelligence and machine learning with GIS to automatically recognize complex patterns—such as the perimeter and thermal profile of a wildfire—across vast volumes of imagery and sensor data.

Data Model of Reality (Virkelighetsmodell)

A simplified digital representation of a physical object or phenomenon consisting of geometry (position and shape) and attributes (descriptive properties), retaining only the information necessary for a defined purpose.

Geometry (in GIS)

The spatial component of a geographic data model that answers 'where' by defining the shape and location of an object mathematically as a point, line, or polygon using coordinates.

Attributes (in GIS)

The non-spatial descriptive data stored in tabular form that answers 'what' by recording the characteristics, qualities, or measurements of an object independently of its coordinates.

Vector Model

A spatial data model that represents discrete features with precise, explicit boundaries using coordinate-based geometries: points (single coordinate pairs), lines (ordered paths), and polygons (closed areas).

Raster Model

A spatial data model that represents geographic space as a continuous, regular grid of cells where each cell is assigned a specific value, making it ideal for gradually varying phenomena like elevation and vegetation density.

Map (Kart)

A scale-adjusted, generalized, and symbolic visual representation of all or part of the Earth's surface, mathematically constructed using a coordinate reference system and a map projection.

Map Scale

The mathematical ratio between a measured distance on a map and the corresponding distance in the physical terrain, expressed as $\text{Scale} = \frac{\text{Distance on map}}{\text{Distance in reality}}$.

Large Scale vs. Small Scale

Large scale maps (e.g., $1:5\,000$) have a larger fraction value and display small geographic extents in high detail, whereas small scale maps (e.g., $1:500\,000$) have a smaller fraction value and cover broad areas with heavily reduced detail.

Graphic Scale

A visual scale bar drawn directly on a map that maintains correct proportions and accurate distance readings even if a printed or displayed map is physically enlarged or reduced.

Theorema Egregium

A fundamental mathematical theorem establishing that a curved surface (such as the Earth's ellipsoid) cannot be projected onto a flat plane without introducing geometric distortion in shape, area, distance, or direction.

Map Projection

A mathematical formulation used to transfer coordinates from the Earth's three-dimensional curved surface onto a two-dimensional flat plane, requiring an intentional compromise among preserving shape, area, distance, or direction.

Cartographic Generalization

The deliberate four-step process of selection, simplification, aggregation, and symbolization applied to geographical features to ensure a map remains legible and clear at a chosen scale.

Map Signs / Symbols (Karttegn)

Standardized graphical expressions—categorized by points, lines, polygons, colors, and icons—interpreted via a legend to convey specific feature types without textual descriptions.

GIS Equation

The defining relationship $\text{MAP} + \text{DATA} + \text{ANALYSIS} = \text{GIS}$, signifying that while a static map merely displays geographic features, GIS provides the database and tools required to query, model, and interpret them.

Thematic Layer (Temalag)

An independent, topic-specific dataset in GIS that groups objects of a single feature class (e.g., roads or parcels) together, allowing multi-layered spatial overlay because all layers share a common coordinate reference system.

Geographic Database (Geodatabase)

A structured digital storage system that models real-world features as table rows, linking a geometry column directly to attribute columns through a permanent unique identifier.

Unique Identifier (Unique ID)

An unchanging, non-reusable identification number (e.g., ID $1024$ for the USN Bø campus building) that securely anchors geometry to attributes and external relational tables, preventing errors caused by changing names or addresses.