Process either anticyclones or cyclones

The choice is made with a command line argument. We need this fix
following the evolution of program `eddy_graph`. We now have to check
that the interpolated eddies are in the chosen graph so it makes sense
to create function `set_attribute`. Note that we no longer create the
attribute cyclone of nodes.

Analysis/report_graph.py

 #!/usr/bin/env python3
 
-"""edgelist.csv must be in the current directory."""
+"""edgelist_anti.csv or edgelist_cyclo.csv must be in the current
+directory."""
 
 import networkx as nx
 import csv
@@ -34,33 +35,28 @@ def read_eddy_graph(edgelist, shp_tr_dir = None, read_interp = True):
         # Assuming that the directory containing the interpolated
         # eddies is in the same location as edgelist:
         extremum = path.join(path.dirname(edgelist), "SHP_triplet", "extremum")
-
-        with shapefile.Reader(extremum) as s_read:
-            for shape_rec in s_read:
-                n = (shape_rec.record.date_index, shape_rec.record.eddy_index)
-                G.add_node(n, coordinates = tuple(shape_rec.shape.points[0]),
-                           cyclone = shape_rec.record.cyclone == 1,
-                           interpolat = True, speed = shape_rec.record.speed,
-                           ssh = shape_rec.record.ssh)
+        
+        set_attribute(G, extremum)
 
     if shp_tr_dir is not None:
         # Read and set attributes of Visible eddies:
-        
         extremum = path.join(shp_tr_dir, "extremum")
-
-        with shapefile.Reader(extremum) as s_read:
-            for shape_rec in s_read:
-                n = (shape_rec.record.date_index, shape_rec.record.eddy_index)
-                if shape_rec.record.valid == 1 and n in G:
-                    G.add_node(n,
-                               coordinates = tuple(shape_rec.shape.points[0]),
-                               cyclone = shape_rec.record.cyclone == 1,
-                               interpolat = shape_rec.record.interpolat == 1,
-                               speed = shape_rec.record.speed,
-                               ssh = shape_rec.record.ssh)
+        set_attribute(G, extremum)
 
     return G
 
+def set_attribute(G, extremum):
+    with shapefile.Reader(extremum) as s_read:
+        for shape_rec in s_read:
+            n = (shape_rec.record.date_index, shape_rec.record.eddy_index)
+            if (shape_rec.record.valid == 1
+                or shape_rec.record.interpolat == 1) and n in G:
+                G.add_node(n,
+                           coordinates = tuple(shape_rec.shape.points[0]),
+                           interpolat = shape_rec.record.interpolat == 1,
+                           speed = shape_rec.record.speed,
+                           ssh = shape_rec.record.ssh)
+    
 def to_eddy_agraph(G):
     my_subgraphs = {}
 
@@ -116,9 +112,12 @@ if __name__ == "__main__":
                         action = "store_true")
     parser.add_argument("--interp", help = "Read interpolated eddies",
                         action = "store_true")
+    parser.add_argument("orientation", help ="Choose a graph",
+                        choices = ["anti", "cyclo"])
     args = parser.parse_args()
     
-    G = read_eddy_graph("edgelist.csv", read_interp = args.interp)
+    G = read_eddy_graph(f"edgelist_{args.orientation}.csv",
+                        read_interp = args.interp)
 
     if args.node is None:
         H = G