Trail Line Visualization

Overview

When tracking a specific callsign, the map displays a trail line (polyline) connecting all position points chronologically at zoom levels ≤ 8, instead of showing a heat map.

User Experience

Viewing Trail Lines

Search for and track a callsign using the search box
Zoom out to level 8 or below
A blue trail line appears connecting all positions in chronological order
The trail line respects the "Trail Duration" setting (1 hour, 6 hours, etc.)

Zoom Behavior

Zoom ≤ 8 + Tracking: Trail line visible
Zoom > 8 + Tracking: Individual markers visible
Zoom ≤ 8 + No tracking: Heat map visible
Zoom > 8 + No tracking: Individual markers visible

Technical Details

Backend

DisplayManager.send_trail_line_for_tracked_callsign/1 - Generates trail line data
DisplayManager.handle_zoom_threshold_crossing/2 - Handles mode switching
Trail line data filtered by packet_age_threshold (trail duration setting)
Points sorted chronologically by received_at timestamp

Frontend

MapHook.trailLine - Leaflet Polyline instance
Event: show_trail_line - Display trail line
Event: clear_trail_line - Remove trail line
Trail line cleared when switching to heat map or markers

Styling

Color: #3B82F6 (blue-500)
Weight: 3 pixels
Opacity: 0.8
Line Cap/Join: round
Interactive: true

Continuous Path Connection

Trail lines connect all points regardless of distance between them. This is important for:

High-altitude balloons traveling long distances
Aircraft on cross-country flights
Stations with intermittent coverage gaps
Showing complete journey paths

No distance-based filtering or gap detection is applied. The trail always shows the complete chronological path within the trail duration.

Future Enhancements

Direction arrows along the trail
Time-based gradient coloring (old → new)
Click on trail to show packet details
Line simplification for very long trails
Multiple callsign tracking with different colors

2 KiB Raw Blame History