GPXWeaver

A powerful, web-based GPX track editor for simplifying, editing, splitting, and joining GPS tracks. Perfect for cleaning up recorded tracks from apps like GeoTracker before sharing or analyzing.

🔗 Live App: https://asg49.github.io/GPXWeaver/

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Features

⚡ Performance

• Fast load for massive files — tested with 500,000+ points in 120MB+ GPX files
• Toggle-only marker visibility — no automatic recalculation on zoom, fast zooming at any scale
• Clean default — only the track line is shown on load; markers appear only when you ask for them

📉 Track Simplification

• Douglas-Peucker algorithm for intelligent point reduction
• Manual simplification at any percentage (1–95%)
• Restore Original restores the pre-simplify state — including all manual edits made before simplifying
• Simplification always works from the current edited state — manually added, dragged, or deleted points are never lost

📍 Points Visibility

• Manual toggle only — "●○ Points OFF / ● Points ON" controls all marker display
• No automatic zoom-based marker loading — zoom freely without performance hits
• Marker colors: 🔴 Red (normal/delete mode) · 🟠 Orange (split mode)

✏️ Track Editing

• Drag points — move any point to adjust position (6 decimal place precision)
• Add points — tap the track line to insert new waypoints with interpolated ele, time, speed, and course
• Delete points — long-press (2.6s) on any point to mark for deletion
• Rectangle Selection — draw a rectangle to bulk-select and delete multiple points (mobile and desktop)
• All edits survive subsequent simplification operations ✓

✂️ Track Splitting

• Split mode — tap any point to divide the track at that location
• Save individual segments as separate GPX files

🔗 Track Joining — Smart Chaining

• Select 2+ files and they join automatically in the correct order
• Auto-detection of file type:
  • GeoTracker recordings (have timestamps) → sorted chronologically by recording date
  • Google Maps routes (no timestamps) → chained by geographic proximity of endpoints
• Starting track auto-identified; greedy nearest-neighbor eliminates stray connecting lines
• Browser file selection order and alphabetical filename order are irrelevant

🌐 Gap Detection

• Logarithmic gap threshold slider (10m – 1,000km)
• Prevents unwanted connector lines between segments
• Adjustable in real time

🗺️ Map Layers

• OpenStreetMap · OpenTopoMap · Google Terrain (default) · Google Satellite · Google Hybrid · Esri World Imagery

📊 Navigation Controls

Desktop: Zoom display + Points toggle (bottom-left) · Scale bar (bottom-right) · Layer selector (top-right)

Mobile: Zoom display (top-left) · Points toggle (top-right) · Scale bar (bottom-right)

💾 File Handling

• Save filename uses the actual disk filename, not the internal GPX track name
• Edited files get _X suffix (e.g. MyHike_X.gpx)
• Current filename shown in header bar; updates to _X on first edit
• Saved GPX includes <metadata> with:
  • <name>: the save filename
  • <time>: the original recording date from the first trackpoint — ensures correct chronological sorting in GeoTracker
  • Falls back to current date for timestampless files (Google Maps routes)
• All original <trkpt> data preserved: elevation, time, speed, course, extensions
• Coordinate precision: always 6 decimal places (~0.11m)
• GeoTracker extensions (<geotracker:meta c="course" s="speed"/>) preserved and interpolated for added points

🔒 Security

• sanitizeHTML() on all track name display
• sanitizeXML() on all GPX output

📱 Mobile-Optimized

• Responsive layout; touch-friendly controls including rectangle selection
• Compact header with current filename

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Usage

Getting Started

1. Load — Menu (☰) → Load GPX File → select file(s)
2. View — blue track line shown immediately
3. Show markers — "●○ Points OFF" → "● Points ON"
4. Edit — drag, tap to add, long-press to delete, or rectangle-select to bulk-delete
5. Simplify — Menu → adjust slider → Apply Simplification (edits are preserved)
6. Save — Menu → Save GPX → saves with _X suffix and original recording date

Joining GeoTracker Recordings

1. Menu → Load GPX File → select all recording files
2. GPXWeaver sorts them chronologically by recording timestamp
3. Join All Tracks → saved file retains original recording date for correct GeoTracker sorting

Joining Google Maps Routes

1. Generate segments (max 10 waypoints each) → convert with maptogpx.com
2. Menu → Load GPX File → select all segment files
3. GPXWeaver chains them geometrically by endpoint proximity → Join All Tracks

Edit Then Simplify (Correct Workflow)

1. Load file → simplify at desired % if needed
2. Add/drag/delete points as needed
3. Simplify again if needed — all manual edits are preserved ✓
4. Save

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File Format

• Input: .gpx (GPX 1.0 and 1.1)
• Output: GPX 1.1, all original <trkpt> data preserved
• Metadata: filename + original recording date
• Coordinates: 6 decimal places
• Namespaces: declared at root <gpx> level

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Technical Details

• Single HTML file — no install, works offline after first load
• Leaflet.js · Douglas-Peucker · Haversine distance formula
• Geometric nearest-neighbor chaining (Google Maps) · Chronological sort (GeoTracker)
• originalTrackpoints kept in sync with all manual edits — simplification never loses work
• All event listeners inside DOMContentLoaded · XSS protection throughout

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Changelog

v7.0 (2026-07-24) — CRITICAL FIX

• Manual edits no longer lost after re-simplification
• Root cause: applySimplify() always ran from originalTrackpoints (frozen at load time)
• Points added/dragged/deleted only existed in trackpoints — second simplify wiped them
• Fix: applySimplify() snapshots trackpoints → originalTrackpoints before simplifying
• dragend, point-add, deleteSelectedPoints(), deleteSegmentAndSplit() all now sync originalTrackpoints
• Restore Original correctly restores post-edit pre-simplify state ✓

v6.9 (2026-07-24)

• <metadata><time> uses first trackpoint timestamp (original recording date)
• GeoTracker chronological sorting preserved in saved files
• Falls back to current date for timestampless files

v6.8 (2026-07-24)

• chainTracks() dispatcher: chronological for GeoTracker, geometric for Google Maps
• chronologicalSortTracks() added

v6.7 (2026-07-23)

• Fixed maxIncomingDist initialization (Infinity → -Infinity)
• Geometric chaining now correctly identifies starting track

v6.6 (2026-07-23)

• Geometric nearest-neighbor track chaining replaces alphabetical sort
• haversineDistance() and geometricChainTracks() added

v6.5 (2026-07-22)

• Gap Detection slider initialized correctly inside DOMContentLoaded
• accent-color added to both sliders

v6.3 (2026-07-20)

• cleanInnerXML() strips redundant xmlns from trkpt innerHTML
• Files now load cleanly in all GPX applications

v6.2 (2026-07-19)

• All event listeners inside DOMContentLoaded
• <metadata> block in all saved GPX files
• Coordinate precision fixed to 6 decimal places throughout

v6.0 (2026-07-15)

• GeoTracker <geotracker:meta> extensions parsed, preserved, and interpolated
• Major code audit: XSS sanitization, dead code removal, logic consistency

v5.99–v5.95 (2026-07-15)

• Full <trkpt> innerHTML preserved · filename in header · disk filename on save
• Toggle-only point visibility · all event listeners and security hardened

v5.94 (2026-06-24)

• Rectangle selection fixed on mobile (changedTouches)

v5.87 (2026-06-18)

• Mobile controls: zoom top-left, toggle top-right, scale bottom-right

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License

MIT License — see LICENSE for details.

Author

Tony Gozdz © 2026 · Battery R&D Engineer · Serious GPX Geek 🗺️

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Tested with files from 100 to 500,000+ points (120MB+ GPX). All operations — drag, add, delete, rectangle select, split, join, simplify — work reliably on mobile and desktop. Manual edits always survive re-simplification.