Geospatial Technology and GIS Fundamentals

Comprehensive vocabulary flashcards covering geospatial technologies, the GeoData life cycle, GeoBIM, GIS concepts, remote sensing, spatial data models, attribute management, and geocoding.

Geospatial Technology

A broad category of mapping, surveying, and spatial systems—including GPS, GIS, remote sensing, cartography, spatial analysis, and location-based services—used to store, label, analyze, and visualize spatial information.

Location-Based Services (LBS)

Software applications and services that utilize real-time geographic data from a mobile device or positioning system to provide information, navigation, or services tailored to a user's location.

GeoData Life Cycle

A structured four-stage framework—comprising Collect, Combine, Collaborate, and Consume—used to harness spatial data and analytics to resolve complex societal, environmental, and planning problems.

Data Lineage

The end-to-end documentation capturing the complete journey of data, from its origin and initial creation through its transformation and combination, to its final consumption or destruction.

Collect Stage

The first phase of the GeoData Life Cycle, determining the objective, collection timeframe, and methods (such as surveys, sensors, crowdsourcing, or fieldwork) to acquire primary or secondary qualitative and quantitative data.

Combine Stage

The second phase of the GeoData Life Cycle, involving the aggregation, reclassification, transformation, and fusion of diverse data sources using common identifiers or shared spatial references.

Collaborate Stage

The third phase of the GeoData Life Cycle, focusing on centralized storage, data access governance, security frameworks, and distribution across shared platforms like GeoPortals using standard file formats.

Consume Stage

The fourth phase of the GeoData Life Cycle, unlocking the analytical value of data through modeling, predictive analytics, correlation analysis, and visual representations such as maps, charts, and dashboards to guide decision-making.

Geospatial Data

Information that describes objects, events, or features with a specific physical location on or near Earth's surface by combining locational coordinates, descriptive attributes, and temporal information.

Building Information Modeling (BIM)

A process involving the generation and management of digital representations of the physical and functional characteristics of built places and diverse physical infrastructure to support asset lifecycle decisions.

GeoBIM

The integration of Geospatial Information Systems (GIS) and Building Information Modeling (BIM), bridging broad, universal regional spatial contexts with detailed, specific engineering information of individual buildings.

Digital Twin

A scale-accurate, geo-referenced virtual model of physical assets that incorporates live data streams from sensors and building management systems to monitor, simulate, and optimize planning and operational efficiency.

Geographic Information System (GIS)

A multi-component technological environment designed to capture, manage, store, visualize, and analyze data alongside its spatial counterpart.

Spatial Analysis

The process of extracting information, recognizing patterns, and discovering statistical or spatial relationships from one or more layers of geographic data using quantitative techniques.

Coordinate Reference System (CRS)

A defined framework that relates coordinates on a two-dimensional flat map directly to real-world locations on the curved surface of the Earth using an underlying globe model.

Geographic Coordinate System (GCS)

A three-dimensional spherical reference system that defines real-world positions on the Earth's surface using angular units of measurement (latitude and longitude).

Datum

A mathematical model of the Earth's shape defined by angular units, a reference starting origin point $(0,0)$, and the orientation of an ellipsoid or spheroid relative to the center of Earth's mass.

WGS 84

The World Geodetic System 1984; a globally referenced horizontal datum commonly utilized for international mapping, GPS navigation, and online spatial services.

SVY21

The standard horizontal coordinate reference system and datum established for national mapping, cadastral surveys, and localized geospatial data in Singapore.

Singapore Height Datum (SHD)

The designated vertical datum used in Singapore to establish standard vertical elevations and orthometric heights relative to mean sea level.

Projected Coordinate System (PCS)

A flat, two-dimensional reference system that applies mathematical transformations to convert angular coordinates from a GCS into planar Cartesian coordinates $(x, y)$ with linear units of measure.

Planar Projection

A map projection (also termed an azimuthal projection) created by projecting features of the Earth's surface onto a flat plane touching the globe at a single tangent point or along a secant line.

Cylindrical Projection

A map projection created by mathematically projecting the Earth's surface onto a surrounding cylinder, which can touch the globe along one line of tangency or two lines in a secant case.

Mercator Projection

A cylindrical map projection developed by Gerardus Mercator in $1569$ that preserves angles, local directions, and shapes of small objects while severely distorting the relative size of features toward the polar regions.

Conical Projection

A map projection constructed by projecting the Earth's surface onto a cone tangent or secant to the globe, minimizing distortion along lines of tangency and commonly used for mid-latitude regions.

Remote Sensing

The science and technique of acquiring imagery and quantitative physical properties of features on the Earth's surface from a distance without direct physical contact.

Spatial Resolution

The level of spatial detail depicted in an image, determined by pixel size; smaller pixel dimensions provide higher resolution and sharper structural detail.

Spectral Resolution

The specific wavelength range and number of electromagnetic spectral bands measured by a sensor; narrower bands provide higher spectral resolution.

Temporal Resolution

The revisit time or interval of time required for a remote sensing satellite or platform to complete a full orbit cycle and re-image the identical geographical location.

Active Sensor

A remote sensing instrument that provides its own energy source to illuminate a target surface and subsequently measures the reflected backscatter radiation (e.g., radar, LiDAR).

Passive Sensor

A remote sensing instrument that detects and measures naturally occurring energy, such as reflected sunlight or emitted thermal radiation from Earth's surface (e.g., Landsat, Sentinel).

LiDAR

Light Detection and Ranging; an active optical remote sensing technique that transmits pulses of laser light to measure distances and construct detailed digital elevation models on land.

Sonar

Sound Navigation and Ranging; an active acoustic sensing technique that uses sound propagation underwater to measure depths and model subaquatic topography.

Geostationary Orbit

A high-altitude circular orbit directly above the equator where a satellite matches the rotational period of the Earth, remaining continuously stationary over a single location.

Sun-Synchronous Orbit

A near-polar orbit designed so that the satellite passes over any given geographic point at the exact same local solar time, ensuring uniform sun angles and lighting conditions.

Vector Data Model

A spatial representation model that defines discrete real-world features using explicit coordinate geometry consisting of points, lines, and polygons.

Point (Vector Geometry)

A zero-dimensional vector feature represented by an individual coordinate pair $(X, Y)$, used to model discrete features such as bus stops, lampposts, and trees.

Line (Vector Geometry)

A one-dimensional vector feature formed by a series of connected coordinate points, used to represent linear geographic features such as roads, rivers, and MRT lines.

Polygon (Vector Geometry)

A two-dimensional vector feature formed by an ordered sequence of vertices enclosing a defined geographic area, used to represent buildings, boundaries, and lakes.

Raster Data Model

A spatial representation model that structures continuous or categorical real-world phenomena into a regular grid or matrix of equal-sized cells (pixels) organized in rows and columns.

Modifiable Areal Unit Problem (MAUP)

A statistical bias and analytical challenge in GIS where spatial analysis results change when individual point data are aggregated into arbitrarily delineated geographic zones.

Scale Effect

A component of the Modifiable Areal Unit Problem (MAUP) where different analytical outcomes and statistical patterns occur strictly as a function of the size or level of aggregation of the spatial unit.

Zonal Effect

A component of the Modifiable Areal Unit Problem (MAUP) where varying the shape or boundary placement of spatial units at the same scale produces major discrepancies in analytical findings.

Nominal Data

A qualitative level of measurement comprising discrete descriptive categories without any natural hierarchy, mathematical order, or directional ranking (e.g., street names, land use types).

Ordinal Data

A qualitative level of measurement where attribute values fall into ordered, ranked classes or scales, though the mathematical intervals between ranks are not uniform (e.g., service ratings, road hierarchy).

Interval Data

A quantitative measurement level characterized by uniform, meaningful intervals between numbers, but lacking an absolute or true zero point (e.g., temperature in degrees Celsius).

Ratio Data

A quantitative measurement level characterized by uniform intervals between numbers and a true, non-arbitrary zero point denoting the absolute absence of the variable (e.g., width of a canal, population count).

Geocoding

The computational process of converting descriptive physical addresses or location descriptions into absolute spatial coordinate pairs (latitude and longitude) referenced to a CRS such as WGS 84.

Reversed Geocoding

The computational process of translating geographic coordinate pairs into a human-readable street address or location name.

Latitude

Imaginary horizontal coordinate lines (parallels) that run east-west across the globe, measuring angular distance in degrees north or south from the Equator $0^{\circ}$.

Longitude

Imaginary vertical coordinate lines (meridians) that run north-south between Earth's poles, measuring angular distance in degrees east or west from the Prime Meridian $0^{\circ}$.