Data Sources & Methodology

Transparent documentation of our geographic data sources and calculation methods

Data Quality Commitment

TrueCountrySizes is built on authoritative, public domain geographic data from recognized institutions. We prioritize accuracy, transparency, and academic rigor in all our calculations.

Last Updated: January 2026 |Next Review: July 2026 |Countries Covered: 195 UN member states + territories

Primary Data Sources

🌍

Natural Earth

Primary source for country boundaries

What We Use:

  • •Admin 0 Countries (1:50m scale)
  • •Admin 1 States & Provinces (USA, Canada)
  • •Physical features (coastlines, lakes)

Why Natural Earth:

  • •Public domain (no licensing restrictions)
  • •Maintained by professional cartographers
  • •Designed specifically for web mapping
  • •Regular updates and quality control

Source:Natural Earth | License: Public Domain | Version: 5.1.2 (2023)

📊

World Bank Open Data

Country metadata and statistics

What We Use:

  • •Official country names and codes
  • •Land area measurements (km²)
  • •Regional classifications
  • •Population data (for context)

Data Quality:

  • •Updated annually
  • •Cross-validated with national statistics
  • •Standardized methodology across countries
  • •Open data with full documentation

Source:World Bank Open Data | License: CC BY 4.0 | Updated: Annually

🏳️

REST Countries API

Country flags and additional metadata

What We Use:

  • •Country flag URLs and SVGs
  • •Alternative country names
  • •Capital cities
  • •Currency information

Integration:

  • •Cached locally for performance
  • •Fallback for missing data
  • •Regular synchronization

Source:REST Countries | License: MIT | Maintained by: Open source community

Calculation Methodology

True Size Calculation

Our core algorithm preserves the geodesic area of countries while allowing them to be repositioned on the Mercator projection. This shows how latitude affects apparent size.

Step-by-Step Process:

  1. Calculate the original centroid of the country using geodesic methods
  2. Determine the distance and bearing from centroid to each polygon vertex
  3. When repositioning, maintain these geodesic distances and bearings
  4. Project new coordinates onto Mercator for visual display
  5. The Mercator projection naturally handles the visual scaling effect

Mathematical Foundation: Uses Turf.js geodesic calculations based on the WGS84 ellipsoid model of Earth. Mercator scaling factor: 1/cos(latitude).

Area Measurements

Calculation Method:

  • •Geodesic area calculation (spherical geometry)
  • •WGS84 ellipsoid model (not perfect sphere)
  • •Accounts for Earth's flattening at poles
  • •Excludes territorial waters and ice shelves

Accuracy Standards:

  • •±0.1% for countries > 100,000 km²
  • •±0.5% for countries < 100,000 km²
  • •Cross-validated with CIA World Factbook
  • •Rounded to nearest 1,000 km² for display

Size Distortion Formula

The Mercator projection scales areas by the square of the secant of latitude. Our size change indicators use this formula:

scale_factor = 1 / cos(latitude_radians)
area_scale = scale_factor²
size_change = (new_area / original_area - 1) × 100%

At 60° Latitude:

Countries appear 4× larger than actual size

At the Equator:

Countries show their true relative size

Data Processing Pipeline

1

Raw Data Collection

Download latest datasets from Natural Earth and World Bank. Verify checksums and file integrity. Convert shapefiles to GeoJSON format.

2

Geometry Simplification

Simplify polygon geometries for web performance while maintaining geographic accuracy. Use Douglas-Peucker algorithm with 0.01° tolerance.

3

Validation & Quality Control

Validate geometries, check for self-intersections, verify area calculations against authoritative sources, and ensure all countries have complete metadata.

4

Optimization & Deployment

Compress GeoJSON files, generate pre-calculated comparison data, create search indexes, and deploy to CDN for fast global access.

Accuracy & Limitations

What We Excel At

  • ✓Accurate relative size comparisons
  • ✓Real-time geodesic calculations
  • ✓Mercator distortion visualization
  • ✓Up-to-date political boundaries
  • ✓Cross-platform consistency

Known Limitations

  • !Disputed territories may vary between sources
  • !Small islands may be omitted from simplified geometries
  • !Historical borders not included (current only)
  • !Maritime boundaries not visualized
  • !Web Mercator has ±85° latitude limits

Update Schedule

Automatic Updates

  • Country Metadata: Monthly sync with World Bank data
  • Flag Images: Weekly sync with REST Countries API
  • Performance Monitoring: Daily calculation accuracy checks

Manual Reviews

  • Boundary Changes: Reviewed quarterly for political updates
  • Major Revisions: Annual review of Natural Earth releases
  • Algorithm Updates: Continuous improvement based on user feedback

Academic Citations

How to Cite TrueCountrySizes

APA Format:

TrueCountrySizes. (2026). Interactive country size comparison tool. Retrieved from https://truecountrysizes.com

MLA Format:

"TrueCountrySizes: Interactive Country Size Comparison." TrueCountrySizes, 2026, truecountrysizes.com.

For Researchers

If you're using TrueCountrySizes data in academic research, please also cite our primary sources (Natural Earth, World Bank) as they provide the foundational geographic data. Our contribution is the interactive visualization and true-size calculation methodology.

Questions About Our Data?

We're committed to transparency and accuracy. If you notice any discrepancies, have questions about our methodology, or need access to our processed datasets, please reach out.

Contact Our Data TeamExplore the Data