DataTerminology.comNEW
Also known as: GCS
A reference system using latitude and longitude to locate positions on Earth.
DESCRIPTION
A geographic coordinate system (GCS) defines locations on Earth using angular measurements on a spherical or ellipsoidal model, typically latitude and longitude with an associated datum such as WGS84. GCS is foundational for mapping, GIS analysis, and spatial data integration. Accurate use requires understanding datums, axis order, and units. EPSG codes catalog standardized GCS definitions and transformations. Converting between GCS and projected systems is common for analysis and visualization.
ALTERNATIVE DEFINITIONS
Wikipedia
A geographic coordinate system (GCS) is a coordinate system that enables every location on Earth to be specified by a set of numbers, letters or symbols.
Highlights universal specification of locations on Earth using coordinates.
Esri GIS Dictionary
A coordinate system that uses latitude and longitude to define locations on a spherical or ellipsoidal model of the earth.
Emphasizes the role of lat/long and the spherical/ellipsoidal Earth model.
RELATED TERMS
Latitude Longitude Datum WGS 84 Map Projection EPSG Codes Geodesy Geographic Information System Coordinate Reference System
COMPETING TERMS
Projected Coordinate System
KNOWLEDGE AREAS
Data Science Semantic & Knowledge Modeling Data Modeling Data Visualization Data Architecture
TARGET AUDIENCE
Data Scientist Data Engineer Data Analyst Data Architect Data Modeler BI Specialist
EXTERNAL SOURCES
- Wikipedia - Geographic coordinate system
- Esri - ArcGIS Pro guide to GCS
- OGC - OGC CRS definitions
- IOGP EPSG - EPSG CRS registry
TOP QUESTIONS
What is a Geographic Coordinate System in GIS?
A GCS defines positions on Earth using latitude and longitude with a specific datum, enabling global mapping and spatial analysis.
Category: Definition
Why does datum choice matter in a Geographic Coordinate System?
Different datums model Earth’s shape differently, causing coordinate shifts. Using the wrong datum can introduce location errors and misalign spatial layers.
Category: Risks
How is a Geographic Coordinate System used with EPSG codes?
EPSG codes uniquely identify GCS definitions and transformations, simplifying consistent reference in GIS tools and data exchange.
Category: Practice
What’s the difference between a Geographic Coordinate System and a Projected Coordinate System?
GCS uses angular coordinates on a sphere/ellipsoid; projected systems convert the Earth to a flat plane for distance/area accuracy in local analyses.
Category: Alternatives
What are common mistakes with Geographic Coordinate Systems?
Mixing datums, assuming axis order always lon-lat, and reprojecting incorrectly can lead to misaligned maps and inaccurate measurements.
Category: Mistakes
How do I convert from a Geographic Coordinate System to a projection?
Use a GIS tool to define the source CRS and apply a proper transformation to the target projected CRS, ensuring datum compatibility.
Category: HowTo
What is currently a hot topic around Geographic Coordinate Systems?
High-precision GNSS and dynamic datums for tectonic motion are advancing CRS definitions and time-dependent transformations.
Category: Topic
How are Geographic Coordinate Systems managed in enterprise GIS?
Standardize CRS usage, document EPSG codes, enforce metadata, and validate transformations in data pipelines and catalogs.
Category: Management
When should I prefer WGS84 as a Geographic Coordinate System?
WGS84 is widely adopted for global datasets and web maps; it’s a safe default when cross-system interoperability is required.
Category: Opinion