diff --git a/geotrek/core/path_router.py b/geotrek/core/path_router.py
index d334b1b4b9..60551e7db1 100644
--- a/geotrek/core/path_router.py
+++ b/geotrek/core/path_router.py
@@ -9,7 +9,7 @@
 
 import numpy as np
 from scipy.sparse.csgraph import dijkstra
-from scipy.sparse import csr_array
+from scipy.sparse import lil_array
 
 from geotrek.common.utils import sqlfunction
 from .models import Path
@@ -111,7 +111,7 @@ def set_cs_graph(self):
             return
 
         nb_of_nodes = len(self.nodes)
-        self.dijk_matrix = csr_array((nb_of_nodes, nb_of_nodes), dtype=np.float32)
+        self.dijk_matrix = lil_array((nb_of_nodes, nb_of_nodes), dtype=np.float32)
 
         nodes_list = list(self.nodes.items())
         for i, (key1, value1) in enumerate(nodes_list[:-1]):