diff --git a/app/scodoc/sco_report.py b/app/scodoc/sco_report.py
index 6d1bcb7c..8dfd60bc 100644
--- a/app/scodoc/sco_report.py
+++ b/app/scodoc/sco_report.py
@@ -41,6 +41,7 @@ from flask import url_for, g
 import pydot
 
 import app.scodoc.sco_utils as scu
+from app.models import NotesFormModalite
 from app.scodoc import notesdb as ndb
 from app.scodoc import html_sco_header
 from app.scodoc import sco_codes_parcours
@@ -1269,14 +1270,19 @@ def graph_parcours(
         return "", etuds, bacs, bacspecialites, annee_bacs, civilites, statuts
     edges = scu.DictDefault(
         defaultvalue=set()
-    )  # {(formsemestre_id_origin, formsemestre_id_dest) : etud_set}
+    )  # {("SEM"formsemestre_id_origin, "SEM"formsemestre_id_dest) : etud_set}
+
+    def sem_node_name(sem, prefix="SEM"):
+        "pydot node name for this integer id"
+        return prefix + str(sem["formsemestre_id"])
+
     sems = {}
     effectifs = scu.DictDefault(defaultvalue=set())  # formsemestre_id : etud_set
     decisions = scu.DictDefault(defaultvalue={})  # formsemestre_id : { code : nb_etud }
-    isolated_nodes = []
-    connected_nodes = set()
+    isolated_nodes = []  # [ node_name_de_formsemestre_id, ... ]
+    connected_nodes = set()  # { node_name_de_formsemestre_id }
     diploma_nodes = []
-    dem_nodes = {}  # formsemestre_id : noeud pour demissionnaires
+    dem_nodes = {}  # formsemestre_id : noeud (node name) pour demissionnaires
     nar_nodes = {}  # formsemestre_id : noeud pour NAR
     for etud in etuds:
         nxt = {}
@@ -1295,14 +1301,17 @@ def graph_parcours(
                 ):
                     # cas particulier du diplome puis poursuite etude
                     edges[
-                        ("_dipl_" + s["formsemestre_id"], nxt["formsemestre_id"])
+                        (
+                            sem_node_name(s, "_dipl_"),
+                            sem_node_name(nxt),  # = "SEM{formsemestre_id}"
+                        )
                     ].add(etudid)
                 else:
-                    edges[(s["formsemestre_id"], nxt["formsemestre_id"])].add(etudid)
-                connected_nodes.add(s["formsemestre_id"])
-                connected_nodes.add(nxt["formsemestre_id"])
+                    edges[(sem_node_name(s), sem_node_name(nxt))].add(etudid)
+                connected_nodes.add(sem_node_name(s))
+                connected_nodes.add(sem_node_name(nxt))
             else:
-                isolated_nodes.append(s["formsemestre_id"])
+                isolated_nodes.append(sem_node_name(s))
             sems[s["formsemestre_id"]] = s
             effectifs[s["formsemestre_id"]].add(etudid)
             nxt = s
@@ -1315,18 +1324,18 @@ def graph_parcours(
                     dc[dec["code"]] = 1
             # ajout noeud pour demissionnaires
             if nt.get_etud_etat(etudid) == "D":
-                nid = "_dem_" + s["formsemestre_id"]
+                nid = sem_node_name(s, "_dem_")
                 dem_nodes[s["formsemestre_id"]] = nid
-                edges[(s["formsemestre_id"], nid)].add(etudid)
+                edges[(sem_node_name(s), nid)].add(etudid)
             # ajout noeud pour NAR (seulement pour noeud de depart)
             if (
                 s["formsemestre_id"] == formsemestre_id
                 and dec
                 and dec["code"] == sco_codes_parcours.NAR
             ):
-                nid = "_nar_" + s["formsemestre_id"]
+                nid = sem_node_name(s, "_nar_")
                 nar_nodes[s["formsemestre_id"]] = nid
-                edges[(s["formsemestre_id"], nid)].add(etudid)
+                edges[(sem_node_name(s), nid)].add(etudid)
 
             # si "terminal", ajoute noeud pour diplomes
             if s["semestre_id"] == nt.parcours.NB_SEM:
@@ -1335,8 +1344,8 @@ def graph_parcours(
                     and code_semestre_validant(dec["code"])
                     and nt.get_etud_etat(etudid) == "I"
                 ):
-                    nid = "_dipl_" + s["formsemestre_id"]
-                    edges[(s["formsemestre_id"], nid)].add(etudid)
+                    nid = sem_node_name(s, "_dipl_")
+                    edges[(sem_node_name(s), nid)].add(etudid)
                     diploma_nodes.append(nid)
     #
     g = scu.graph_from_edges(list(edges.keys()))
@@ -1350,12 +1359,12 @@ def graph_parcours(
         g.set_bgcolor("#fffff0")  # ou 'transparent'
     # titres des semestres:
     for s in sems.values():
-        n = g.get_node(s["formsemestre_id"])[0]
+        n = g.get_node(sem_node_name(s))[0]
         log("s['formsemestre_id'] = %s" % s["formsemestre_id"])
         log("n=%s" % n)
-        log("get=%s" % g.get_node(s["formsemestre_id"]))
+        log("get=%s" % g.get_node(sem_node_name(s)))
         log("nodes names = %s" % [x.get_name() for x in g.get_node_list()])
-        if s["modalite"] and s["modalite"] != "FI":
+        if s["modalite"] and s["modalite"] != NotesFormModalite.DEFAULT_MODALITE:
             modalite = " " + s["modalite"]
         else:
             modalite = ""
@@ -1373,9 +1382,9 @@ def graph_parcours(
         n.set_fontsize(8.0)
         n.set_width(1.2)
         n.set_shape("box")
-        n.set_URL("formsemestre_status?formsemestre_id=" + s["formsemestre_id"])
+        n.set_URL(f"formsemestre_status?formsemestre_id={s['formsemestre_id']}")
     # semestre de depart en vert
-    n = g.get_node(formsemestre_id)[0]
+    n = g.get_node("SEM" + str(formsemestre_id))[0]
     n.set_color("green")
     # demissions en rouge, octagonal
     for nid in dem_nodes.values():
@@ -1440,7 +1449,7 @@ def graph_parcours(
         )
 
         def repl_title(m):
-            fid = m.group("fid")
+            fid = int(m.group("fid"))
             title = sems[fid]["titreannee"]
             if decisions[fid]:
                 title += (