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%) — no auto-simplification
• Restore Original to undo simplification at any time
• Simplification respects your current marker visibility setting

📍 Points Visibility

• Manual toggle only — "●○ Points OFF / ● Points ON" button 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 (coordinates rounded to 6 decimal places)
• 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 (works on mobile and desktop)
• All edits update the track line in real time

✂️ Track Splitting

• Split mode — tap any point to divide the track at that location
• Save individual segments as separate GPX files
• Split markers auto-clean after save

🔗 Track Joining

• Smart multi-file loading — select 2+ files and they join automatically
• Select 1 file = load normally; select multiple = auto-join

🌐 Gap Detection

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

🗺️ Map Layers

• OpenStreetMap
• OpenTopoMap (topographic contours)
• 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 (below +/− buttons)
• Points toggle — top-right
• Scale bar — bottom-right

💾 File Handling

• Save filename uses the actual disk filename you loaded, not the internal GPX track name
• Edited files get _X suffix (e.g. MyHike_X.gpx)
• Saved GPX always includes a <metadata> block with save filename and UTC timestamp
• All original <trkpt> data preserved on save: elevation, time, speed, course, extensions
• Coordinate precision: always 6 decimal places (~0.11m — more than sufficient for GPS)
• GeoTracker extensions (<geotracker:meta c="course" s="speed"/>) fully preserved and interpolated for added points

🔒 Security

• HTML sanitization on all track name display (sanitizeHTML())
• XML sanitization on all GPX output (sanitizeXML())
• Protects against malicious GPX files with injected content

📱 Mobile-Optimized

• Responsive layout for phones and tablets
• Touch-friendly controls including rectangle selection (fixed changedTouches for reliable touch-end detection)
• Compact header with current filename displayed

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Usage

Getting Started

1. Load a GPX file — Menu (☰) → Load GPX File → select file(s)
   • Select multiple files to auto-join them
2. View your track — blue line shown immediately; no markers until you ask
3. Show markers — click "●○ Points OFF" → becomes "● Points ON"
4. Edit — drag points, tap line to add, long-press to delete, or draw a rectangle to bulk-delete
5. Simplify — Menu → adjust slider → Apply Simplification → Restore Original if needed
6. Save — Menu → Save GPX → file saves with _X suffix using your original filename

Rectangle Selection (Bulk Delete)

1. Menu → Enable "Rectangle Select"
2. Draw a rectangle over the points you want to remove
3. Tap "Delete Selected" to remove them all at once

Splitting a Track

1. Menu → Enable "Split Mode"
2. Tap the point where you want to split
3. Save → downloads as separate GPX files

Joining Tracks

• Auto: Menu → Load GPX File → select 2+ files at once
• Manual: Menu → Load Multiple Files → Join All Tracks

Gap Detection (Joined Tracks)

• Menu → adjust Gap Detection slider
• Increase to hide connector lines between segments
• Works in real time

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File Format

• Input: .gpx files (GPX 1.0 and 1.1)
• Output: GPX 1.1, all original <trkpt> data preserved (ele, time, speed, course, extensions)
• Metadata: <metadata> block added to every saved file with name and timestamp
• Coordinates: 6 decimal places in all output

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Map Controls Summary

Control	Desktop	Mobile
Zoom +/−	top-left	top-left
Zoom display	bottom-left	top-left
Points toggle	bottom-left	top-right
Layer selector	top-right	top-right
Scale bar	bottom-right	bottom-right

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Technical Details

• Single HTML file — no dependencies to install, works offline after first load
• Leaflet.js mapping library
• Douglas-Peucker simplification algorithm
• File System Access API for save location control
• All event listeners properly registered inside DOMContentLoaded
• XSS protection on all user-generated content inserted into HTML or XML

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Recent Improvements (v5.95–v6.2)

✅ v6.2 — Code correctness & GPX metadata

• All event listeners moved inside DOMContentLoaded (was causing menu/layer control failures)
• GPX <metadata> block (filename + UTC timestamp) added to all saved files
• Coordinate precision fixed to 6 decimal places in all three GPX generators
• CSS header conflict fixed (duplicate #header rule with position: relative was hiding header)

✅ v6.1 — Coordinate precision

• Dragged and added points now stored and output at 6 decimal places (was 15+)

✅ v6.0 — GeoTracker data preservation

• Full <trkpt> innerHTML preserved on load and save (speed, course, extensions, all tags)
• interpolateSpeed() and interpolateCourse() for added points (with 0°/360° wrap handling)
• Comprehensive code audit: XSS sanitization, dead code removal, duplicate function removed, logic consistency

✅ v5.99 — trkpt round-tripping

• All three GPX generators now output innerXML verbatim for existing points
• Synthesized points fall back to ele/time only

✅ v5.98 — Header filename display

• Current filename shown in header bar (right-aligned, between title and ☰)
• Updates to _X suffix on first edit; clears on track clear; hidden in join mode

✅ v5.97 — Save filename fix

• Save now uses the actual disk filename, not the internal GPX <name> tag
• markAsEdited() appends _X to the disk filename

✅ v5.96 — Security & logic audit

• sanitizeHTML() and sanitizeXML() added and applied throughout
• Removed duplicate generateGPXForTrack(), dead code, unused constants
• All createMarkers() calls now respect toggle-only rule

✅ v5.95 — Toggle-only marker visibility

• Removed all auto-zoom-based marker display
• zoomend handler does safety cleanup only — no marker recalculation
• Fast zooming at any zoom level, any file size

✅ v5.94 — Rectangle selection mobile fix

• Root cause: e.touches is empty on touchend (finger already lifted)
• Fixed getEventPoint() to use e.changedTouches
• Rectangle selection now works reliably on mobile

✅ v5.87 — Mobile control layout

• Zoom at top-left, Points toggle at top-right, scale at bottom-right on mobile
• Desktop unchanged: zoom + toggle at bottom-left

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Changelog

v6.2 (2026-07-19)

• Fixed all event listeners to be inside DOMContentLoaded (menu and layer dropdown were broken)
• Added <metadata> block (filename + UTC timestamp) to all saved GPX files
• Fixed coordinate precision to 6 decimal places in generateGPXForTrack() (was using raw float)
• Fixed CSS duplicate #header rule hiding the header bar
• Fixed deleteSelectedPoints() to use disk filename for _X suffix

v6.1 (2026-07-19)

• Fixed dragged points: stored at 6 decimal places (was full float precision ~15 digits)
• Fixed added points: stored at 6 decimal places
• Fixed multitrack GPX generators: toFixed(7) → toFixed(6)

v6.0 (2026-07-15)

• Parses GeoTracker <geotracker:meta c="course" s="speed"/> extensions
• interpolateSpeed() and interpolateCourse() for added points
• Added points now include interpolated extensions in their innerXML
• Major code audit: XSS sanitization, dead code removal, brace/indentation fixes, operator precedence, consistent creator version across all GPX generators

v5.99 (2026-07-15)

• All <trkpt> data preserved through edits via innerXML capture on parse
• All three GPX generators output innerXML verbatim for existing points

v5.98 (2026-07-15)

• Filename displayed in header bar (right-aligned, italic, truncates if too long)
• Cleared on track clear; not shown in join mode

v5.97 (2026-07-15)

• Save uses actual disk filename (not internal GPX track name)
• markAsEdited() appends _X to disk filename, updates header display

v5.96 (2026-07-15)

• sanitizeHTML() and sanitizeXML() added; applied to all track name insertions
• Removed duplicate generateGPXForTrack() function
• Removed dead adjustSimplifyForTarget(), unused ZOOM_THRESHOLD constants, empty stubs
• All createMarkers() calls enforce toggle-only rule
• clearMarkers() state management fixed
• clearSelection() null-check on getElement()
• Fixed percentToTolerance() indentation, operator precedence in interactive: option
• All three GPX generators use consistent creator="GPXWeaver vX.X"

v5.95 (2026-07-15)

• Removed all automatic zoom-based marker visibility
• zoomend handler now only does safety cleanup
• Toggle button sole control: "●○ Points OFF" / "● Points ON"
• Fast zooming at any zoom level, no recalculation overhead

v5.94 (2026-06-24)

• Fixed rectangle selection on mobile (e.changedTouches instead of e.touches)
• Fixed clearMarkers() to always remove markers from map

v5.87 (2026-06-18)

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

v5.83 (2026-06-14)

• Fixed unconditional marker creation after simplification and restore

v5.69 (2026-06-13)

• Smart multi-file auto-join
• Logarithmic gap threshold slider (10m–1,000km)
• Restore Original button; auto-simplification removed

v5.45 and earlier

• Core features: rectangle selection, track splitting/joining, gap detection, Douglas-Peucker simplification, multi-map layers, lazy marker loading

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License

MIT License — see LICENSE file for details.

Author

Tony Gozdz © 2026
Battery & 3D Printing R&D Engineer · Serious GPX Geek 🗺️

Support

Open an issue on GitHub with your browser/device info and a description of the problem.

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Tested with files from 100 to 500,000+ points (120MB+ GPX). Handles extreme files efficiently. All editing operations — drag, add, delete, rectangle select, split, join, simplify — work reliably on both mobile and desktop.