Peaky Finders

An iPhone app for hikers in the Western North Carolina mountains. It reads your GPS location and compass heading, then shows a map of nearby summits with a bearing arrow and distance for each one. Tap any peak to get a live compass arrow and a satellite map framing you and the summit.

What it does

• Plots all peaks from peaks.json within a user-adjustable radius (0–100 km) on a satellite map
• Tap a peak marker → detail sheet with a rotating arrow that points straight up when you're facing the summit, plus the distance in km
• The range slider re-filters the map in real time

Requirements

• Xcode 26+
• iOS 26+ device or simulator (portrait, iPhone-only)
• Real device strongly recommended — the magnetometer/heading sensor rarely resolves on a simulator, leaving the UI on "Acquiring heading…"

Building

The project name contains a space — always quote paths in shell commands.

# Build for simulator
xcodebuild -project "Peaky Finders.xcodeproj" \
           -scheme "Peaky Finders" \
           -destination 'platform=iOS Simulator,name=iPhone 16' \
           build

# List available schemes/targets
xcodebuild -list -project "Peaky Finders.xcodeproj"

There are no external dependencies (no SPM packages, no CocoaPods). Everything is first-party SwiftUI + CoreLocation + MapKit.

Info.plist note

Peaky-Finders-Info.plist is an empty dict by design. The project uses GENERATE_INFOPLIST_FILE = YES, so the real Info.plist is synthesized at build time from INFOPLIST_KEY_* build settings in project.pbxproj. Location usage strings (NSLocationWhenInUseUsageDescription) live there — edit build settings, not the plist file.

Architecture

Data flows one way: CoreLocation → LocationProvider → views.

LocationProvider (CLLocationManager delegate)
    │
    ▼
ContentView (authorization + sensor gate)
    │
    ▼
SightingsMapView (map + range slider)
    │   tap marker
    ▼
SightingView (bearing arrow + detail map)

File	Role
LocationProvider.swift	@Observable wrapper for CLLocationManager. Publishes authorizationStatus, currentLocation, and heading (true-north degrees, nil when invalid).
ContentView.swift	Root view. Guards on authorization then on sensor availability, then renders SightingsMapView.
Peak.swift	Peak model (Codable/Identifiable). Bearing and distance helpers. Great-circle bearing math (CLLocationCoordinate2D.bearing(to:)). Preview/debug constants.
Sighting.swift	Immutable snapshot of a peak's bearing and distance from a specific location. SightingView is the tap-to-open detail sheet.
PeakCatalog.swift	Loads and decodes peaks.json once at startup via PeakCatalog.all. Traps on failure — a missing or malformed bundle file is a build bug, not a runtime condition.
GeoViews.swift	Reusable UI: HeadingDisplay (numeric heading text), BearingDisplay (rotating compass arrow), DistanceDisplay (km label).
SightingsMapView.swift	Map with peak markers and a range slider. Presents SightingView as a sheet on marker tap.
DebugViews.swift	Scrollable list of all sightings with arrows and distances. Not shown in production; used by previews and for layout testing.
peaks.json	Runtime peak dataset — Western NC summits. Add or edit peaks here; the app reads this at launch.

Adding peaks

Edit peaks.json. Each entry needs a unique name, a latitude, and a longitude:

{ "name": "Max Patch", "latitude": 35.79389, "longitude": -82.95833 }

The name is the stable identifier — duplicates will cause the second entry to shadow the first in SwiftUI lists.

Current peak list

Peak	Elevation (approx.)
Mount Mitchell	6,684 ft — highest peak in eastern North America
Celo Knob	6,327 ft
Waterrock Knob	6,292 ft
Cold Mountain	6,030 ft
Mount Pisgah	5,721 ft
Richland Balsam	6,410 ft
Black Balsam Knob	6,214 ft
Shining Rock	6,040 ft
Devil's Courthouse	5,720 ft
Tanasee Bald	5,840 ft