Location & Maps

You MUST use this skill for ANY location services, mapping, geofencing, or Core Location / MapKit work.

Quick Reference

Symptom / Task	Reference
Authorization strategy (When In Use vs Always)	See skills/core-location.md
Monitoring approach (continuous, significant-change, CLMonitor)	See skills/core-location.md
Accuracy selection, background location	See skills/core-location.md
CLLocationUpdate, CLMonitor, CLServiceSession APIs	See skills/core-location-ref.md
Authorization API patterns, geofencing API	See skills/core-location-ref.md
Compass heading, heading reference body (headingBody)	See skills/core-location-ref.md (Part 12)
Location updates never arrive	See skills/core-location-diag.md
Background location stops working	See skills/core-location-diag.md
Authorization always denied, geofence failures	See skills/core-location-diag.md
SwiftUI Map, annotations, markers, clustering	See skills/mapkit.md
MKMapView vs SwiftUI Map decision	See skills/mapkit.md
Search, directions, routing	See skills/mapkit.md
MapKit API: Marker, Annotation, MKLocalSearch, MKDirections	See skills/mapkit-ref.md
Look Around, MKMapSnapshotter, MKMapItem	See skills/mapkit-ref.md
Annotations not appearing, region jumping	See skills/mapkit-diag.md
Clustering not working, search failures	See skills/mapkit-diag.md
Overlay rendering, user location not showing	See skills/mapkit-diag.md

Decision Tree

digraph location {
    start [label="Location / Maps task" shape=ellipse];
    domain [label="Core Location or MapKit?" shape=diamond];
    cl_type [label="Need what?" shape=diamond];
    mk_type [label="Need what?" shape=diamond];

    start -> domain;

    domain -> cl_type [label="Core Location"];
    domain -> mk_type [label="MapKit / Maps"];

    cl_type -> "skills/core-location.md" [label="authorization, monitoring\nstrategy, accuracy,\nbackground location"];
    cl_type -> "skills/core-location-ref.md" [label="API syntax\n(CLLocationUpdate,\nCLMonitor, CLServiceSession)"];
    cl_type -> "skills/core-location-diag.md" [label="something broken\n(no updates, denied,\ngeofence not firing)"];

    mk_type -> "skills/mapkit.md" [label="patterns, decisions\n(SwiftUI Map vs MKMapView,\nannotations, search)"];
    mk_type -> "skills/mapkit-ref.md" [label="API syntax\n(Marker, Annotation,\nMKLocalSearch, MKDirections)"];
    mk_type -> "skills/mapkit-diag.md" [label="something broken\n(annotations missing,\nregion jumping, clustering)"];
}

1. Authorization strategy, monitoring approach, accuracy? → skills/core-location.md 1a. Need specific API syntax (CLLocationUpdate, CLMonitor, CLServiceSession)? → skills/core-location-ref.md 1b. Location not working? → skills/core-location-diag.md
2. Adding a map, annotations, search, directions? → skills/mapkit.md 2a. Need specific MapKit API syntax (Marker, MKLocalSearch, MKDirections)? → skills/mapkit-ref.md 2b. Map display broken? → skills/mapkit-diag.md
3. Location draining battery? → See axiom-performance (skills/energy.md)
4. Background task scheduling for location? → See axiom-integration
5. Privacy manifest for location? → See axiom-integration

Conflict Resolution

location vs axiom-performance: When location is draining battery:

1. Try location FIRST — Excessive accuracy or continuous updates are the #1 cause. skills/core-location.md covers accuracy selection and monitoring strategy.
2. Only use axiom-performance if location settings are already correct — Profile after ruling out obvious over-tracking.

location vs axiom-integration: When implementing background location:

• Background location configuration (Info.plist, capabilities, CLServiceSession) → use location
• BGTaskScheduler for periodic location processing → use axiom-integration

location vs axiom-data: When storing or syncing location data:

• Getting location updates, geofencing → use location
• Persisting location history, CloudKit sync → use axiom-data

location vs axiom-build: When location permissions fail in simulator:

• Authorization dialogs, Info.plist keys → use location (skills/core-location-diag.md)
• Simulator GPS simulation, simctl location → use axiom-build

Critical Patterns

Core Location (skills/core-location.md):

• Authorization escalation strategy (When In Use first, Always later)
• Monitoring decision tree (continuous vs significant-change vs CLMonitor)
• Accuracy selection with battery impact
• Background location configuration
• Anti-patterns with time costs (premature Always authorization, unnecessary continuous updates)

Core Location API (skills/core-location-ref.md):

• CLLocationUpdate AsyncSequence (iOS 17+)
• CLMonitor condition-based geofencing (iOS 17+)
• CLServiceSession declarative authorization (iOS 18+)
• Authorization API patterns, background mode configuration

Core Location Diagnostics (skills/core-location-diag.md):

• Location updates never arrive
• Background location stops working
• Authorization always denied
• Geofence events not triggering
• Location accuracy unexpectedly poor

MapKit (skills/mapkit.md):

• SwiftUI Map vs MKMapView decision tree
• Annotation patterns (Marker, custom Annotation)
• Search (MKLocalSearch, autocomplete)
• Directions and routing
• Anti-patterns (annotations in view body, no view reuse, setRegion loops)

MapKit API (skills/mapkit-ref.md):

• SwiftUI Map API (MapCameraPosition, content builders, controls)
• MKMapView delegate patterns
• MKLocalSearch, MKDirections
• Look Around, MKMapSnapshotter
• Clustering configuration

MapKit Diagnostics (skills/mapkit-diag.md):

• Annotations not appearing (lat/lng swapped, missing delegate)
• Map region jumping/looping (updateUIView guard)
• Clustering not working (missing clusteringIdentifier)
• Search returning no results (resultTypes, region bias)
• Overlay rendering failures

Anti-Rationalization

Thought	Reality
"Just request Always authorization upfront"	30-60% denial rate. Request When In Use first, escalate later. skills/core-location.md covers the strategy.
"Continuous updates are fine for my use case"	Continuous updates drain battery even when the app doesn't need sub-second location. Use significant-change or CLMonitor.
"I'll use MKMapView, it's more flexible"	SwiftUI Map covers most use cases since iOS 17. MKMapView means UIViewRepresentable boilerplate. skills/mapkit.md has the decision tree.
"Annotations in the view body is fine for a few items"	Annotations recreate on every view update. Even 50 items cause hitches. Move to model with @State or @Observable.
"I know how geofencing works"	CLMonitor (iOS 17+) replaces legacy region monitoring with conditions. The API changed significantly.
"Background location just needs the capability"	It needs Info.plist keys, capability, CLServiceSession (iOS 18+), AND correct authorization level. Missing any one silently fails.
"I'll handle location errors later"	Authorization denial is not an error — it's the default state. Handle it from the start.

Example Invocations

User: "How do I request location permissions?" → Read: skills/core-location.md

User: "What's the CLLocationUpdate API?" → Read: skills/core-location-ref.md

User: "My location updates never arrive" → Read: skills/core-location-diag.md

User: "How do I add a map with pins?" → Read: skills/mapkit.md

User: "What's the SwiftUI Map API?" → Read: skills/mapkit-ref.md

User: "My annotations aren't showing on the map" → Read: skills/mapkit-diag.md

User: "How do I implement geofencing?" → Read: skills/core-location.md then skills/core-location-ref.md

User: "Location is draining battery" → Read: skills/core-location.md, then See axiom-performance (skills/energy.md)

User: "How do I add search to my map?" → Read: skills/mapkit.md then skills/mapkit-ref.md