map: Show grid spacing

Author: MichelleRos

MAVProxy/modules/mavproxy_map/mp_slipmap_ui.py

@@ -355,6 +355,7 @@ def __init__(self, parent, state):
         self.last_click_pos = None
         self.last_click_pos_used_for_text = None
         self.last_terrain_height = None
+        self.grid_spacing = None
         if state.elevation != "None":
             state.ElevationMap = mp_elevation.ElevationModel(database=state.elevation)
 
@@ -479,6 +480,10 @@ def update_position(self):
                 alt = state.ElevationMap.GetElevation(lat, lon)
                 if alt is not None:
                     newtext += ' %.1fm %uft' % (alt, alt*3.28084)
+        
+        if self.grid_spacing is not None:
+            newtext += f" Grid Spacing: {self.grid_spacing:.0f}m"
+
         state.mt.set_download(state.download)
         pending = 0
         if state.download:
@@ -594,7 +599,9 @@ def redraw_map(self):
 
         # possibly draw a grid
         if state.grid:
-            SlipGrid('grid', layer=3, linewidth=1, colour=(255,255,0)).draw(img, self.pixmapper, bounds)
+            self.grid_spacing = SlipGrid('grid', layer=3, linewidth=1, colour=(255,255,0)).draw(img, self.pixmapper, bounds)
+        else:
+            self.grid_spacing = None
 
         # draw layer objects
         keys = state.layers.keys()

MAVProxy/modules/mavproxy_map/mp_slipmap_util.py

@@ -357,7 +357,7 @@ def draw_line(self, img, pixmapper, pt1, pt2, colour, linewidth):
     def draw(self, img, pixmapper, bounds):
         '''draw a polygon on the image'''
         if self.hidden:
-            return
+            return None
         (lat,lon,w,h) = bounds
         # note that w and h are in degrees
         spacing = 1000
@@ -387,6 +387,8 @@ def draw(self, img, pixmapper, bounds):
             pos1 = mp_util.gps_newpos(start[0], start[1], 0, i*spacing)
             pos3 = (pos1[0], pos1[1]+w*2)
             self.draw_line(img, pixmapper, pos1, pos3, self.colour, self.linewidth)
+        
+        return spacing
 
 
 class SlipFlightModeLegend(SlipObject):