Bug fix: adapt the central longitude

Adapt the central longitude of the projection, depending on window or
position of chosen node. Else we can have arrows crossing the whole projection.

Analysis/plot_traj.py

@@ -58,7 +58,7 @@ def plot_nbunch(G, nbunch, color = '#1f78b4', label = None, ax = None):
     if label is not None:
         for n in nbunch:
             if is_node_type(G, n, label):
-                xy = ccrs.PlateCarree().transform_point(*pos[n], src_crs)
+                xy = ax.projection.transform_point(*pos[n], src_crs)
                 ax.annotate(str(n), xy, color = color, xytext = (2, 2),
                             textcoords = 'offset points')
 
@@ -106,7 +106,6 @@ if __name__ == "__main__":
     print("Reading edgelist.csv in current directory...")
     G = report_graph.read_eddy_graph("edgelist.csv", args.shp_tr_dir)
     plt.figure()
-    ax = plt.axes(projection=ccrs.PlateCarree())
 
     if args.window is not None:
         if args.window[2] - args.window[0] > 360:
@@ -116,13 +115,18 @@ if __name__ == "__main__":
             if plot_eddy_contours.in_window(d["coordinates"], args.window):
                 if "component" not in d: report_graph.add_component(G, n)
 
+        dest_crs = ccrs.PlateCarree((args.window[0] + args.window[2]) / 2)
+        ax = plt.axes(projection = dest_crs)
         plot_all_components(G, args.label)
     elif args.node is not None:
         source = tuple(args.node)
         report_graph.add_component(G, source)
+        dest_crs = ccrs.PlateCarree(G.nodes[source]["coordinates"][0])
+        ax = plt.axes(projection = dest_crs)
         plot_nbunch(G, G.nodes[source]["component"], label = args.label)
     else:
         assign_all_components(G)
+        ax = plt.axes(projection = ccrs.PlateCarree())
         plot_all_components(G, args.label)
 
     ax.coastlines()