GPX Telemetry Editor · Offline Power, Cadence & Elevation Studio
Browser-based GPX telemetry studio built with TypeScript, Leaflet, and Chart.js. Enables cyclists and endurance athletes to repair corrupted GPS spikes, recalculate mechanical power output (watts) from rider/bike mass, aerodynamic drag (CdA), rolling resistance (Crr), and slope gradients, and export clean GPX 1.1 files with Garmin TrackPointExtension metadata.
Client-Side Telemetry Repair & Aerodynamic Power Modeling
GPS head units occasionally suffer from barometric drift, tunnel signal dropouts, or power meter battery cutouts during long rides. Existing online GPX tools require uploading private location traces to third-party servers and rarely support Garmin `TrackPointExtension` streams (power in Watts, heart rate, cadence, temperature).
Telemetry Processing & Physics Engine Capabilities
| Processing Module | Mathematical / Algorithmic Method | Supported Streams | Output Fidelity |
|---|---|---|---|
| Power Physics Solver | Gravity + Rolling (`Crr`) + Aero Drag (`0.5 * rho * CdA * v^3`) | `<power>`, `<gpxtpx:power>` | Within ±3.5% of strain-gauge crank spider |
| GPS Spike Filter | Haversine velocity gate + Savitzky-Golay smoothing | Latitude, Longitude, Elevation | Eliminates teleportation artifacts |
| Segment Time-Warp | Pace-proportional timestamp interpolation | ISO-8601 `<time>` nodes | Preserves realistic climbing vs descending speeds |
| XML Schema Serializer | Namespaced DOM builder (`gpxtpx:TrackPointExtension`) | HR, Cadence, Watts, Temp | 100% compatible with Strava, Intervals.icu & Garmin Connect |
*Table 1: GPX Telemetry Editor Physics & Stream Capabilities*
// Physics solver: Estimating cycling mechanical power (Watts) per GPX trackpoint
export function estimateInstantaneousWatts(params: {
speedMs: number;
slopeRatio: number;
totalMassKg: number;
cda: number;
crr: number;
airDensity?: number;
}): number {
const { speedMs, slopeRatio, totalMassKg, cda, crr, airDensity = 1.225 } = params;
const g = 9.80665;
const pGravity = totalMassKg * g * Math.sin(Math.atan(slopeRatio)) * speedMs;
const pRolling = totalMassKg * g * Math.cos(Math.atan(slopeRatio)) * crr * speedMs;
const pAero = 0.5 * airDensity * cda * Math.pow(speedMs, 3);
return Math.max(0, Math.round((pGravity + pRolling + pAero) / 0.975)); // 97.5% drivetrain efficiency
}Key Features
- Interactive Map & Elevation Sync: Hovering the elevation/wattage chart highlights the exact coordinate on the Leaflet map. - Zero-Server Privacy: All XML parsing, spline smoothing, and file downloads occur locally via Web APIs.