diff --git a/Analysis/plot_snapshot.py b/Analysis/plot_snapshot.py
index 9de421371f992b37dc7602dbcd696b8d30508487..1b2ac0cf3f2127097150ddb6df29f7393e5dbdcf 100755
--- a/Analysis/plot_snapshot.py
+++ b/Analysis/plot_snapshot.py
@@ -28,9 +28,9 @@ import cartopy.crs as ccrs
 from os import path
 from cartopy.mpl import geoaxes
 
-def snapshot(k, shp_tr_dir, *, dashed = False, light = False,
+def snapshot(k, shp_tr_dir, window = None, *, dashed = False, light = False,
              new_figure = False, src_crs = ccrs.PlateCarree(),
-             projection = ccrs.PlateCarree(), window = None):
+             projection = ccrs.PlateCarree()):
     """Plots extrema, outermost contours and max-speed contours.
 
     shp_tr_dir: containing the three shapefiles.
@@ -227,8 +227,8 @@ if __name__ == "__main__":
                 marker = "+", color = "gray", linestyle = "None")
 
     if args.window is None: plot_grid_bb(args.shp_tr_dir, ax)
-    snapshot(args.k, args.shp_tr_dir, dashed = args.dashed,
-             light = args.light, window = args.window)
+    snapshot(args.k, args.shp_tr_dir, args.window, dashed = args.dashed,
+             light = args.light)
 
     if args.velocity:
         with netCDF4.Dataset("uv.nc") as f: