Advanced Map Overlays — Parcel boundaries, neighborhoods, heat maps

[GareBear99]

Overview

Add interactive map overlays for property perimeters, parcel boundaries, and neighborhood zones.

Current State

• GPS map system supports marker overlay and 200m area radius circle
• Overlay toggle UI already exists (bottom-right buttons)
• Map uses accurate meters-per-pixel scaling at all zoom levels

Scope

• Property perimeter — polygon overlay from parcel boundary data
• Neighborhood zones — color-coded area overlays by neighborhood/community
• Heat map — price density or deal score visualization layer
• Comparable radius — adjustable radius ring (200m, 500m, 1km)
• Transit/amenity proximity — nearby schools, transit stops, parks

Data Sources

• Municipal GIS parcel data (many cities provide this as open data)
• OpenStreetMap boundary data
• StatsCan census tract boundaries

Technical Notes

• SVG overlay system in gps-fallback-map.js already supports arbitrary shapes
• Need GeoJSON → screen coordinate projection
• Overlay toggle buttons pattern is established

Acceptance Criteria

• At least parcel boundary overlay for one city
• Toggle buttons for each new overlay type
• No performance degradation with overlays active