refactor: shadowfinder + exif — symmetric metric, inlined sun math, WMM declination

CLAUDE.md

@@ -22,7 +22,7 @@ Single-page app. One route (`/`), one page component (`src/pages/Index.tsx`).
 **Data flow:**
 1. User uploads a photo → `extractPhotoMetadata` (`src/lib/exif.ts`) runs two concurrent `exifr.parse` calls plus `exifr.gps()` to extract timestamp, compass bearing, focal length, and GPS coords into `PhotoMetadata`.
 2. User marks 3 points on the image (object base, object top, shadow tip) via `InteractiveImage`.
-3. "Estimate Location" → `generateShadowFinderGrid` + `analyzeShadowMeasurements` (`src/lib/shadowfinder.ts`) sweep a 0.5° global grid using SunCalc, scoring each point by how well its theoretical shadow ratio matches the measured one.
+3. "Estimate Location" → `generateShadowFinderGrid` + `analyzeShadowMeasurements` (`src/lib/shadowfinder.ts`) sweep a 0.5° global grid using inlined sun-position math (verified against SunCalc in tests), scoring each point by the symmetric angular error `|atan(height/shadow) − sun_altitude|` in radians. Band thresholds (`ULTRA_TIGHT_BAND_RAD`, `MAIN_BAND_RAD`, `VISIBLE_BAND_RAD`, etc.) are exported from `shadowfinder.ts` and consumed by the visualization. `estimateBestLocation` splits bimodal posteriors at the largest latitude gap and uses a circular mean for longitudes so the antimeridian doesn't break the centroid.
 4. Results pass as props to `ShadowFinderVisualization`, which renders a Leaflet heatmap plus optional GPS marker and FOV cone.
 
 **Dual-photo mode:** `Index.tsx` maintains mirrored state for first/second photos (`firstPhotoMeta`/`secondPhotoMeta`, etc.). When both analyses exist, `ShadowFinderVisualization` intersects their high-probability grids and renders a single combined heatmap.

package.json

@@ -22,6 +22,7 @@
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "exifr": "^7.1.3",
+    "geomagnetism": "^0.2.0",
     "leaflet": "^1.9.4",
     "leaflet.heat": "^0.2.0",
     "lucide-react": "^0.462.0",

src/components/AnalysisPanel.tsx

@@ -13,7 +13,7 @@ import {
   formatDateInput,
   formatTimeInput,
 } from '@/lib/exif';
-import { AzimuthConstraint } from '@/lib/shadowfinder';
+import { AzimuthConstraint, DEFAULT_AZIMUTH_TOLERANCE_DEG } from '@/lib/shadowfinder';
 
 interface AnalysisPanelProps {
   points: ClickPoint[];
@@ -80,19 +80,18 @@ export const AnalysisPanel: React.FC<AnalysisPanelProps> = ({
     if (photoMetadata.utcTime) {
       setSelectedDate(formatDateInput(photoMetadata.utcTime));
       setSelectedTime(formatTimeInput(photoMetadata.utcTime));
-    } else if (photoMetadata.localTime) {
-      // Pre-fill local time — user must pick offset
-      setSelectedDate(formatDateInput(photoMetadata.localTime));
-      setSelectedTime(formatTimeInput(photoMetadata.localTime));
+    } else if (photoMetadata.localWallClock) {
+      setSelectedDate(formatDateInput(photoMetadata.localWallClock));
+      setSelectedTime(formatTimeInput(photoMetadata.localWallClock));
     }
   }, [photoMetadata]);
 
   // Recompute displayed UTC time when the user adjusts the offset picker.
   // MUST use useEffect — calling setters during render would cause infinite re-renders.
   // Deps: [manualOffsetMinutes, photoMetadata] — recalculate when either changes.
   useEffect(() => {
-    if (!photoMetadata?.localTime || photoMetadata.utcTime) return;
-    const utc = applyUtcOffset(photoMetadata.localTime, manualOffsetMinutes);
+    if (!photoMetadata?.localWallClock || photoMetadata.utcTime) return;
+    const utc = applyUtcOffset(photoMetadata.localWallClock, manualOffsetMinutes);
     setSelectedDate(formatDateInput(utc));
     setSelectedTime(formatTimeInput(utc));
   }, [manualOffsetMinutes, photoMetadata]);
@@ -119,7 +118,7 @@ export const AnalysisPanel: React.FC<AnalysisPanelProps> = ({
   // Deps: [sunBearingDeg, azimuthEnabled, onAzimuthConstraint] — recalculate on any change.
   useEffect(() => {
     if (sunBearingDeg !== null && azimuthEnabled) {
-      onAzimuthConstraint({ sunBearingDeg, toleranceDeg: 10, enabled: true });
+      onAzimuthConstraint({ sunBearingDeg, toleranceDeg: DEFAULT_AZIMUTH_TOLERANCE_DEG, enabled: true });
     } else {
       onAzimuthConstraint(null);
     }
@@ -149,7 +148,7 @@ export const AnalysisPanel: React.FC<AnalysisPanelProps> = ({
     !photoMetadata ? 'none'
     : photoMetadata.hasGPSTime ? 'gps'
     : photoMetadata.utcOffset ? 'offset'
-    : photoMetadata.localTime ? 'local'
+    : photoMetadata.localWallClock ? 'local'
     : 'none';
 
   return (

src/components/ShadowFinderVisualization.tsx

@@ -5,12 +5,19 @@ import 'leaflet.heat';
 import { Card } from '@/components/ui/card';
 import { Badge } from '@/components/ui/badge';
 import { MapPin, Zap } from 'lucide-react';
-import { ShadowFinderPoint, ShadowAnalysisResult, AzimuthConstraint, applyAzimuthConstraint } from '@/lib/shadowfinder';
+import {
+  ShadowFinderPoint,
+  ShadowAnalysisResult,
+  AzimuthConstraint,
+  applyAzimuthConstraint,
+  VISIBLE_BAND_RAD,
+  NIGHT_LIKELIHOOD,
+} from '@/lib/shadowfinder';
 import { computeFovDeg } from '@/lib/exif';
 
 type HeatPoint = [number, number, number];
 
-const LIKELIHOOD_CUTOFF = 0.15;
+const LIKELIHOOD_CUTOFF = VISIBLE_BAND_RAD;
 
 const WARM_GRADIENT: Record<string, string> = { 0.4: '#FF4500', 0.65: '#FF9500', 0.85: '#FFD700', 1.0: '#FFFF33' };
 const COOL_GRADIENT: Record<string, string> = { 0.4: '#1E90FF', 0.7: '#00E5FF', 1.0: '#FFFFFF' };
@@ -45,7 +52,7 @@ function filterPoints(
   points: ShadowFinderPoint[],
   constraint: AzimuthConstraint | null | undefined
 ): { visible: ShadowFinderPoint[]; fallback: boolean } {
-  const base = points.filter(p => p.likelihood !== -1 && p.likelihood <= LIKELIHOOD_CUTOFF);
+  const base = points.filter(p => p.likelihood !== NIGHT_LIKELIHOOD && p.likelihood <= LIKELIHOOD_CUTOFF);
   if (!constraint?.enabled) return { visible: base, fallback: false };
   const filtered = applyAzimuthConstraint(base, constraint);
   if (filtered.length === 0) return { visible: base, fallback: true };
@@ -246,7 +253,7 @@ export const ShadowFinderVisualization: React.FC<ShadowFinderVisualizationProps>
       const firstPoint = firstMap.get(key);
       if (firstPoint) {
         const combinedLikelihood = Math.max(firstPoint.likelihood, p.likelihood);
-        intersectionPoints.push([p.lat, p.lng, 1 - combinedLikelihood / 0.15]);
+        intersectionPoints.push([p.lat, p.lng, 1 - combinedLikelihood / LIKELIHOOD_CUTOFF]);
       }
     }