Inspired by Ralph Crewe
Geodrome is based on the original "Great Circle Globe" project concept created by science communicator Ralph Crewe. Ralph initially "vibe-coded" the first prototype to explore geodesics, antipodes, and 3D spherical mathematics.
After seeing his demo and receiving his open-source permission to build upon his code, we set out to engineer a modernized, production-ready edition that refactors the codebase into Geodrome while preserving his vision and minimalist aesthetic.
What We Identified & Modernized
Building upon the prototype required solving several core mathematical and rendering challenges:
3D Spherical UV Coordinate Alignment
Three.js SphereGeometry maps texture coordinates differently from standard unadjusted spherical formulas. We aligned the Z-axis coordinate formulas so that raycasting, marker placement, and camera navigation match landmasses with 100% accuracy.
Unified 2D Mercator Projection
Replaced conflicting 2D coordinate transformation functions with a unified lngToX and latToY projection system, resolving longitude inversion bugs and ensuring exact placement for marker dots, antipodes, and landmasses.
Animated Geodesic Tube Growth
Re-engineered path drawing to animate 3D tube geometries over a 3-second frame loop led by a traveling arrow cone, while streaming progressive coordinate points to the 2D Mercator canvas.
Dual-Pass X-Ray Rendering & VRAM Cleanup
Implemented a two-pass rendering engine with THREE.BackSide meshes for hollow sphere transparency, paired with systematic disposeMesh resource cleanup to prevent memory leaks.
Geodesics & Antipodes Explained
A Great Circle is the shortest path between any two points on the surface of a sphere. Unlike straight lines on a flat 2D map, great circles curve according to spherical trigonometry.
An Antipode is the point on Earth's surface diametrically opposite to a given location. Drilling directly through the center of the planet from any point brings you to its exact antipode.