mavproxy_console: avoid exceptions when terrain module unloaded

Author: peterbarker

Diff for: MAVProxy/modules/mavproxy_console.py

@@ -99,6 +99,8 @@ def __init__(self, mpstate):
             self.vehicle_menu = MPMenuSubMenu('Vehicle', items=[])
             self.add_menu(self.vehicle_menu)
 
+        self.shown_agl = False
+
     def cmd_console(self, args):
         usage = 'usage: console <add|list|remove|menu|set>'
         if len(args) < 1:
@@ -391,28 +393,35 @@ def handle_vfr_hud(self, msg):
             lng = master.field('GLOBAL_POSITION_INT', 'lon', 0) * 1.0e-7
             rel_alt = master.field('GLOBAL_POSITION_INT', 'relative_alt', 0) * 1.0e-3
             agl_alt = None
-            if self.settings.basealt != 0:
-                agl_alt = self.module('terrain').ElevationModel.GetElevation(lat, lng)
-                if agl_alt is not None:
-                    agl_alt = self.settings.basealt - agl_alt
-            else:
-                try:
-                    agl_alt_home = self.module('terrain').ElevationModel.GetElevation(home_lat, home_lng)
-                except Exception as ex:
-                    print(ex)
-                    agl_alt_home = None
-                if agl_alt_home is not None:
-                    agl_alt = self.module('terrain').ElevationModel.GetElevation(lat, lng)
+            if self.module('terrain') is not None:
+                elevation_model = self.module('terrain').ElevationModel
+                if self.settings.basealt != 0:
+                    agl_alt = elevation_model.GetElevation(lat, lng)
+                    if agl_alt is not None:
+                        agl_alt = self.settings.basealt - agl_alt
+                else:
+                    try:
+                        agl_alt_home = elevation_model.GetElevation(home_lat, home_lng)
+                    except Exception as ex:
+                        print(ex)
+                        agl_alt_home = None
+                    if agl_alt_home is not None:
+                        agl_alt = elevation_model.GetElevation(lat, lng)
+                    if agl_alt is not None:
+                        agl_alt = agl_alt_home - agl_alt
+            vehicle_agl = master.field('TERRAIN_REPORT', 'current_height', None)
+            if agl_alt is not None or vehicle_agl is not None or self.shown_agl:
+                self.shown_agl = True
                 if agl_alt is not None:
-                    agl_alt = agl_alt_home - agl_alt
-            if agl_alt is not None:
-                agl_alt += rel_alt
-                vehicle_agl = master.field('TERRAIN_REPORT', 'current_height', None)
+                    agl_alt += rel_alt
+                    agl_alt = self.height_string(agl_alt)
+                else:
+                    agl_alt = "---"
                 if vehicle_agl is None:
                     vehicle_agl = '---'
                 else:
                     vehicle_agl = self.height_string(vehicle_agl)
-                self.console.set_status('AGL', 'AGL %s/%s' % (self.height_string(agl_alt), vehicle_agl))
+                self.console.set_status('AGL', 'AGL %s/%s' % (agl_alt, vehicle_agl))
             self.console.set_status('Alt', 'Alt %s' % self.height_string(rel_alt))
             self.console.set_status('AirSpeed', 'AirSpeed %s' % self.speed_string(msg.airspeed))
             self.console.set_status('GPSSpeed', 'GPSSpeed %s' % self.speed_string(msg.groundspeed))