extra info cents assign

Author: sarah-hlsn

doc/user-guide/climada_engine_Impact.ipynb

@@ -861,7 +861,7 @@
     "```\n",
     "exp_lp.assign_centroids(tc, distance=\"euclidean\", threshold=0.1) # assign centroids manually\n",
     "```\n",
-    "The `threshold` argument defines the maximum distance of the nearest neighbor in the units of the `Exposure` crs.\n",
+    "The `threshold` argument defines the maximum distance of the nearest neighbor in the units of the `Exposure` crs.  Setting `threshold` to 0 disables nearest neighbor matching and enforces exact matching. By default twice the highest resolution of the hazard centroids is chosen.\n",
     "\n",
     "When assingning `Centroids` manually, make sure to pass `assign_centroids=False` to the impact calculation, so that the assignment is not lost:\n",
     "```\n",