An interactive educational tool for exploring tidal science, harmonic analysis, and marine navigation planning. Built with React, Three.js, and real astronomical calculations.
Tides aren't just "water goes up, water goes down." They're the result of a complex gravitational dance between Earth, Moon, and Sun—a dance that can be mathematically decomposed into dozens of harmonic constituents, each with its own amplitude, frequency, and phase.
This visualizer helps you understand and explore:
- How tides actually work — The gravitational forces, the bulges, the rotation
- Harmonic analysis — How we predict tides by summing sine waves (constituents)
- Real-world applications — Navigation safety, activity planning, marine operations
Interactive Earth-Moon-Sun system showing real-time gravitational forces and tidal bulges. Watch how the Moon's position creates spring and neap tides.
Educational
- Phasor diagrams showing constituent phase relationships
- Waveform decomposition — see how sine waves combine
- Doodson number explorer
- Interactive quizzes
- Comprehensive glossary
Charts & Analysis
- Real-time tide curves with constituent breakdown
- Frequency spectrum analysis
- Spring/neap calendars
- King tide predictions
- Historical extremes
Navigation & Safety
- Under-keel clearance calculator
- Bridge clearance calculator
- Grounding risk analyzer
- Port approach advisor
- Tidal stream atlas
Activity Planning
- Beach access windows
- Kayak launch planner
- Dive slate generator
- Surf conditions calculator
- Shellfish harvest timing
- Coastal hiking planner
Professional Marine
- Passage planner with tidal gates
- Docking window calculator
- Mooring line calculator
- Fuel consumption estimator
- Crew watch scheduler
1-5— Switch tabs`— Toggle control panelCtrl+K— Search toolsP— Toggle phasor diagramC— Toggle tide curveSpace— Pause/resume time?— Show all shortcuts
- React 19 with TypeScript
- Three.js via React Three Fiber for 3D graphics
- Recharts for data visualization
- astronomy-engine for precise celestial calculations
- Zustand for state management
- Tailwind CSS for styling
- Vite with PWA support
cd tidal-harmonics
npm install
npm run devnpm run build
npm run previewTidal prediction uses harmonic analysis, a technique developed in the 19th century. Each tidal constituent represents a specific astronomical cycle:
| Constituent | Period | Description |
|---|---|---|
| M2 | 12.42 hrs | Principal lunar semidiurnal |
| S2 | 12.00 hrs | Principal solar semidiurnal |
| K1 | 23.93 hrs | Luni-solar diurnal |
| O1 | 25.82 hrs | Principal lunar diurnal |
| N2 | 12.66 hrs | Larger lunar elliptic |
The visualizer includes 37 constituents, covering the major astronomical cycles that influence tides worldwide.
Each constituent has a Doodson number encoding its relationship to six fundamental astronomical frequencies. The explorer lets you decode these numbers and understand what each constituent represents physically.
The Moon's orbit precesses over 18.6 years, causing long-term variations in tidal amplitudes. The nodal correction panel shows where we are in this cycle and how it affects predictions.
Harmonic constants are derived from long-term tide gauge observations. The astronomy calculations use the VSOP87 and ELP/MPP02 theories for planetary and lunar positions.
This project is licensed under the MIT License.
You are free to use, modify, and distribute this software for any purpose, including commercial applications. See the LICENSE file for full terms.
"The tides are a clock that never stops, driven by the patient machinery of the solar system."
