RFCP Iteration 1.5.1: Fixes & Boundaries

Date: January 31, 2025
Type: Bugfix & Polish
Estimated: 2-3 hours
Location: /opt/rfcp/frontend/ + /opt/rfcp/backend/

🎯 Goal

Fix Fresnel endpoint 500 error, restore coverage boundary visualization, minor polish.

🐛 Issues to Fix

1. Fresnel Endpoint 500 Error

Symptom:

curl "/api/terrain/fresnel?tx_lat=48.46&tx_lon=35.05&tx_height=30&rx_lat=48.47&rx_lon=35.06&rx_height=1.5&frequency=1800"
# Returns: 500 Internal Server Error

Location: backend/app/api/routes/terrain.py

Likely cause: Missing rx_height default or async issue in los_service.check_fresnel_clearance()

Fix:

@router.get("/fresnel")
async def check_fresnel(
    tx_lat: float,
    tx_lon: float,
    tx_height: float,
    rx_lat: float,
    rx_lon: float,
    rx_height: float = 1.5,  # Default receiver height
    frequency: float = 1800   # Default frequency MHz
):
    try:
        result = await los_service.check_fresnel_clearance(
            tx_lat, tx_lon, tx_height,
            rx_lat, rx_lon, rx_height,
            frequency
        )
        return result
    except Exception as e:
        raise HTTPException(500, f"Fresnel calculation error: {str(e)}")

Debug: Check backend logs for actual error:

journalctl -u rfcp-backend -n 50 | grep -i error

2. Coverage Boundary Not Showing

Symptom: Boundary contour line (-100 dBm) not visible on map after API integration

Location: frontend/src/components/map/CoverageBoundary.tsx

Likely cause: Component expecting old data format, not new API response

Check:

Is CoverageBoundary still mounted in map?
Does it receive points from coverage store?
Is boundary calculation using correct field (rsrp vs old field name)?

Fix approach:

// CoverageBoundary.tsx
import { useCoverageStore } from '../../store/coverage';

export function CoverageBoundary() {
  const { points, settings } = useCoverageStore();
  
  // Generate boundary from API points
  const boundaryPoints = useMemo(() => {
    if (!points.length) return [];
    
    // Filter points near threshold
    const threshold = settings.min_signal; // -100 dBm
    const tolerance = 5; // ±5 dBm
    
    return points
      .filter(p => Math.abs(p.rsrp - threshold) < tolerance)
      .map(p => [p.lat, p.lon] as [number, number]);
  }, [points, settings.min_signal]);

  // ... rest of boundary rendering
}

Alternative: Use convex hull or marching squares for proper contour:

import { concaveman } from 'concaveman';

const boundaryPolygon = useMemo(() => {
  const edgePoints = points
    .filter(p => p.rsrp >= settings.min_signal && p.rsrp < settings.min_signal + 10)
    .map(p => [p.lon, p.lat]);
  
  if (edgePoints.length < 3) return null;
  
  return concaveman(edgePoints, 2); // concavity factor
}, [points, settings.min_signal]);

3. Minor Polish

a) Stats panel — show models used:

// StatsPanel.tsx
{lastCalculation && (
  <div className="models-used">
    <span className="label">Models:</span>
    <div className="model-tags">
      {lastCalculation.models.map(m => (
        <span key={m} className="model-tag">{m}</span>
      ))}
    </div>
  </div>
)}

b) Loading state during long calculations:

// Show elapsed time during calculation
const [elapsed, setElapsed] = useState(0);

useEffect(() => {
  if (!isCalculating) {
    setElapsed(0);
    return;
  }
  
  const start = Date.now();
  const interval = setInterval(() => {
    setElapsed(Math.floor((Date.now() - start) / 1000));
  }, 1000);
  
  return () => clearInterval(interval);
}, [isCalculating]);

// In render:
{isCalculating && (
  <div className="calculating-status">
    Calculating... {elapsed}s
  </div>
)}

c) Error toast for API failures:

// In coverage store calculateCoverage()
catch (error) {
  const message = error instanceof Error ? error.message : 'Calculation failed';
  toast.error(message); // If using toast library
  set({ error: message, isCalculating: false });
}

✅ Tasks

Fix Fresnel endpoint (backend)
Debug and check logs for actual error
Restore CoverageBoundary with API points
Test boundary renders correctly
Add elapsed time counter during calculation
Add model tags to stats panel
Test all presets still work
Run integration test — should be 21/21

🧪 Testing

# 1. Test Fresnel fix
curl "https://api.rfcp.eliah.one/api/terrain/fresnel?tx_lat=48.46&tx_lon=35.05&tx_height=30&rx_lat=48.47&rx_lon=35.06&rx_height=1.5&frequency=1800"
# Should return: {"clearance_percent": ..., "has_adequate_clearance": ...}

# 2. Run integration test
./rfcp-integration-test.sh
# Should be 21/21

# 3. Visual test
# - Calculate coverage
# - Verify boundary line appears at -100 dBm edge
# - Verify elapsed time shows during calculation

📁 Files to Modify

backend/app/
├── api/routes/terrain.py          # Fresnel fix
└── services/los_service.py        # Check fresnel method

frontend/src/
├── components/
│   ├── map/CoverageBoundary.tsx   # Fix boundary rendering
│   └── panels/
│       ├── CoverageStats.tsx      # Add model tags
│       └── StatsPanel.tsx         # Elapsed time
└── store/coverage.ts              # Error handling

📝 Notes

Boundary can use simple edge detection or proper contour algorithm
concaveman is lightweight (~2KB) for concave hull
Elapsed time helps user know calculation is progressing

Quick iteration — should be fast 🚀

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