trails/openspec/changes/journal-route-previews/design.md
Ullrich Schäfer 6aac8bd885
Add map previews to journal route and activity pages
- Route/activity list pages: map thumbnails with route drawn on OSM tiles
- Route/activity detail pages: interactive Leaflet map with zoom controls
- Server: expose GeoJSON from PostGIS via ST_AsGeoJSON (simplified for lists)
- RouteMapThumbnail component: shared, supports thumbnail and interactive modes
- Placeholder shown for routes/activities without geometry
- Archive journal-route-previews change, sync specs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-04 09:42:07 +01:00

2 KiB

Context

The journal stores route geometry as PostGIS LineString (SRID 4326) in the geom column. The @trails-cool/map package provides MapView and RouteLayer components built on React Leaflet. Currently these are only used by the planner — the journal has zero map UI.

Goals / Non-Goals

Goals:

  • Show route shape on list pages as small map thumbnails that auto-fit to the route bounds
  • Show interactive read-only map on detail pages with route overlay
  • Use existing @trails-cool/map components — no new map library
  • Keep list pages fast (geometry is small as GeoJSON, lazy-load Leaflet)

Non-Goals:

  • Editable maps in the journal (editing happens in the planner)
  • Server-side map image generation (static tiles) — use client-side Leaflet for both
  • Elevation profile on detail pages — future work

Decisions

GeoJSON from PostGIS: Use ST_AsGeoJSON(geom) in SQL queries to convert geometry to GeoJSON strings. Parse on the server and include in loader data. This avoids sending raw GPX to the client just for rendering.

List thumbnails: Small MapView (e.g., 200x150px) with RouteLayer, no controls, no interaction (dragging: false, zoomControl: false). Auto-fit bounds to route with padding. Lazy-loaded via Suspense to keep initial page load fast.

Detail page map: Full-width MapView with standard controls, auto-fit to route. Same RouteLayer component.

Fallback for routes without geometry: Show a placeholder (e.g., muted map icon) when geom is null. This handles legacy routes created before the PostGIS fix.

Risks / Trade-offs

  • List page performance: Many small Leaflet instances could be slow. Mitigate with lazy loading and keeping the component simple (no tile layers until visible via Intersection Observer, or just accept the trade-off for v1).
  • Geometry size: A route with 5000 points produces ~100KB of GeoJSON. For list pages, we could simplify the geometry server-side with ST_Simplify() to reduce payload.