GIS Mapping (Leaflet-First)

Quick Summary

• Leaflet-first mapping for web apps (default engine)
• Optional OpenStreetMap tiles or other providers
• Location selection (marker, polygon, rectangle) + map UI patterns
• Geofencing enforcement with client + server validation (see geofencing.md)
• Performance, clustering, and safe storage of spatial data

Capability Index (Leaflet-First)

1. Basic Mapping & Visualization (core Leaflet)
2. Spatial Queries (Turf.js)
3. Geocoding (Nominatim or Leaflet Control Geocoder)
4. Buffering & Zone Analysis (Turf.js)
5. Heatmaps & Density (leaflet.heat)
6. Routing & Network Analysis (OSRM / GraphHopper + leaflet-routing-machine)
7. Drawing & Editing (leaflet.draw / Geoman)
8. Measurement Tools (leaflet-measure or custom)
9. Clustering & Aggregation (leaflet.markercluster)
10. Spatial Analysis (Turf.js)
11. Time-Based Analysis (custom + heat)
12. Export & Printing (html2canvas/jsPDF + GeoJSON export)

When to Use

• You need interactive maps for customers, assets, farms, or delivery zones
• Users must select or edit locations on a map
• You must enforce geo-fencing or boundary validation
• You need GIS data display with filters, legends, and clustering

Key Patterns

• Leaflet is the default mapping engine.
• Always include attribution for the chosen tile provider.
• Capture geometry in GeoJSON and validate server-side.
• Use bounding-box checks before deeper polygon math.
• Cluster markers when data is large or dense.
• Store optional tile provider API keys in system settings (e.g.,

  osm_api_key

  ) and load them at runtime.
• Default to terrain tiles (OpenTopoMap) for administrative borders.

Leaflet Standardization (BIRDC)

• Use a shared Leaflet configuration for tile URLs, attribution, and defaults.
• Prefer a shared loader or include pattern so Leaflet CSS/JS is consistent across pages.
• Use public/farmer-profile.php as the canonical Leaflet UI reference.

Stack Choices (Frontend)

• Leaflet (default): Lightweight, fastest to implement, best for most apps.
• OpenLayers (optional): Heavyweight GIS controls and projections.
• MapLibre GL JS (optional): Vector tiles, smoother at scale.

Data Model & Storage

• Point:

  latitude

  +

  longitude

  (DECIMAL(10,7))
• Polygon/Boundary: Store as GeoJSON (TEXT/JSON)
• Metadata:

  location_label

  ,

  address

  ,

  last_updated_at

• GeoJSON for portability across JS + backend
• WKT only if your DB tooling depends on it

Map Initialization (Leaflet)

<link
  rel="stylesheet"
  href="https://unpkg.com/leaflet@1.9.4/dist/leaflet.css"
/>
<script src="https://unpkg.com/leaflet@1.9.4/dist/leaflet.js"></script>

const map = L.map("map").setView([0.3476, 32.5825], 12);
const osmApiKey = window.osmApiKey || "";
const osmTileUrl = osmApiKey
  ? `https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png?api_key=${osmApiKey}`
  : "https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png";

const osm = L.tileLayer(osmTileUrl, {
  attribution: "© OpenStreetMap contributors",
  maxZoom: 19,
});

const terrain = L.tileLayer(
  "https://{s}.tile.opentopomap.org/{z}/{x}/{y}.png",
  {
    attribution: "© OpenTopoMap",
    maxZoom: 17,
  },
);

terrain.addTo(map);

Location Selection Patterns

Marker (Point)

• Single click adds/updates a marker
• Store coordinates in hidden inputs

let marker;
map.on("click", (e) => {
  if (marker) map.removeLayer(marker);
  marker = L.marker(e.latlng).addTo(map);
  document.querySelector("#latitude").value = e.latlng.lat;
  document.querySelector("#longitude").value = e.latlng.lng;
});

Polygon / Rectangle (Area)

const drawn = new L.FeatureGroup().addTo(map);
const drawControl = new L.Control.Draw({
  draw: { polygon: true, rectangle: true, marker: false, circle: false },
  edit: { featureGroup: drawn },
});
map.addControl(drawControl);

map.on("draw:created", (e) => {
  drawn.clearLayers();
  drawn.addLayer(e.layer);
  document.querySelector("#boundary_geojson").value = JSON.stringify(
    e.layer.toGeoJSON(),
  );
});

Geofencing (Overview)

• UI constraint: prevent invalid selections in the browser
• Server constraint: verify boundaries in backend validation

UI Patterns

• Filters + stats in a side card, map in a large canvas
• Legend to toggle categories (customer groups, territories)
• Clustering when markers exceed ~200

Performance & UX

• Debounce search and map redraw
• Use marker clustering or server-side tiling
• Lazy load heavy layers
• Simplify large polygons for UI display

Backend Validation

• Ensure latitude is between -90 and 90
• Ensure longitude is between -180 and 180
• Enforce geofence boundaries with the same logic as UI
• Load optional tile provider keys (for example

  osm_api_key

  ) from system settings when building map pages

Privacy & Security

• Location data is sensitive: protect with permissions
• Never trust client-only validation
• Avoid exposing private coordinates without authorization

Recommended Plugins

• Leaflet Draw or Leaflet Geoman (drawing tools)
• Leaflet MarkerCluster (performance)
• Leaflet Control Geocoder (search)
• Turf.js (geospatial analysis)

References

• geofencing.md (sub-skill)
• references/leaflet-capabilities.md
• references/leaflet-arcgis-equivalents.md (index)