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meshview/radio/coverage.py

@@ -1,7 +1,13 @@
 import math
 from functools import lru_cache
 
-from pyitm import itm
+try:
+    from pyitm import itm
+
+    ITM_AVAILABLE = True
+except Exception:
+    itm = None
+    ITM_AVAILABLE = False
 
 DEFAULT_CLIMATE = 5  # Continental temperate
 DEFAULT_GROUND = 0.005  # Average ground conductivity
@@ -48,6 +54,8 @@ def compute_coverage(
     step_km: float,
     reliability: float,
 ) -> list[tuple[float, float, float]]:
+    if not ITM_AVAILABLE:
+        return []
     points = []
     distance = max(step_km, 1.0)
     while distance <= radius_km:
@@ -94,6 +102,8 @@ def compute_perimeter(
     reliability: float,
     threshold_dbm: float,
 ) -> list[tuple[float, float]]:
+    if not ITM_AVAILABLE:
+        return []
     perimeter = []
     distance = max(step_km, 1.0)
     for bearing in range(0, 360, BEARING_STEP_DEG):

meshview/web_api/api.py

@@ -20,6 +20,7 @@ from meshview.radio.coverage import (
     DEFAULT_MIN_DBM,
     DEFAULT_RELIABILITY,
     DEFAULT_THRESHOLD_DBM,
+    ITM_AVAILABLE,
     compute_coverage,
     compute_perimeter,
 )
@@ -1050,6 +1051,12 @@ async def api_coverage(request):
     except (KeyError, ValueError):
         return web.json_response({"error": "Invalid node_id"}, status=400)
 
+    if not ITM_AVAILABLE:
+        return web.json_response(
+            {"error": "Coverage requires pyitm. Run: pip install -r requirements.txt"},
+            status=503,
+        )
+
     def parse_float(name, default):
         value = request.query.get(name)
         if value is None: