Plot grid from `grid_ml.txt` instead of `h.nc`

So read `grid_ml.txt` at the beginning of the script and not in
function `plot_grid_bb`, and pass `grid_nml` instead of `shpc_dir` to
function `plot_grid_bb`.

Inst_eddies/Analysis/plot_eddy_contours.py

@@ -131,15 +131,10 @@ def snapshot(ax, ishape_list, handler, *, dashed = False, light = False,
                 if not light: lines[0].set_marker("o")
                 if dashed: lines[0].set_linestyle("dashed")
 
-def plot_grid_bb(shpc_dir, ax):
+def plot_grid_bb(grid_nml, ax):
     """Grid bounding box."""
-    
-    file = path.join(shpc_dir, "grid_nml.txt")
-    try:
-        grid_nml = f90nml.read(file)["grid_nml"]
-    except FileNotFoundError:
-        print("grid_nml.txt not found. Will not plot bounding box.")
-    else:
+
+    if grid_nml is not None:
         step = grid_nml["STEP_DEG"]
         rect = patches.Rectangle(grid_nml["corner_deg"],
                                  (grid_nml["nlon"] - 1) * step[0],
@@ -171,17 +166,24 @@ if __name__ == "__main__":
                         help = "Save file to specified format")
     args = parser.parse_args()
 
+    if args.grid or args.window is None:
+        file = path.join(args.shpc_dir[0], "grid_nml.txt")
+    
+        try:
+            grid_nml = f90nml.read(file)["grid_nml"]
+        except FileNotFoundError:
+            print("grid_nml.txt not found. Will not plot bounding box.")
+            grid_nml = None
+
     if args.grid:
-        with netCDF4.Dataset("h.nc") as f:
-            if "lon" in f.variables:
-                lon = "lon"
-                lat = "lat"
-            else:
-                lon = "longitude"
-                lat = "latitude"
-                
-            longitude = f[lon][:]
-            latitude = f[lat][:]
+        width = (grid_nml["NLON"] - 1) * grid_nml["STEP_DEG"][0]
+        height = (grid_nml["NLat"] - 1) * grid_nml["STEP_DEG"][1]
+        longitude = np.linspace(grid_nml["CORNER_DEG"][0],
+                                grid_nml["CORNER_DEG"][0] + width,
+                                grid_nml["NLON"])
+        latitude = np.linspace(grid_nml["CORNER_DEG"][1],
+                               grid_nml["CORNER_DEG"][1] + height,
+                               grid_nml["NLat"])
     
     if args.window is not None:
         llcrnrlon, llcrnrlat, urcrnrlon, urcrnrlat = args.window
@@ -212,7 +214,7 @@ if __name__ == "__main__":
         ax.plot(lon_2d.reshape(-1), lat_2d.reshape(-1), transform = src_crs,
                 marker = "+", color = "gray", linestyle = "None")
 
-    if args.window is None: plot_grid_bb(args.shpc_dir[0], ax)
+    if args.window is None: plot_grid_bb(grid_nml, ax)
 
     for shpc_dir in args.shpc_dir:
         handler = util_eddies.open_shpc(shpc_dir)