diff --git a/core/views/editor_helpers.py b/core/views/editor_helpers.py
index c5390cf..4f6dde8 100644
--- a/core/views/editor_helpers.py
+++ b/core/views/editor_helpers.py
@@ -213,7 +213,8 @@ def extract_gps(dict):
         print("failed to find latitude")
 
     location = f'<a href="https://www.openstreetmap.org/?mlat={latitude}&mlon={longitude}">{latitude:09.6f} {latref}, {longitude:010.6f} {lonref}</a>'
-    # 3 digits for longitude, 2 for latitude.
+    # 3 digits for longitude (0-359) or +/-(0-180), 2 for latitude +/-(0-90)
+    # we might want to rectify longitude to be always +(0-359)?
     print(direction)
     print(altitude) 
     print(timestamp_utc)
diff --git a/urls.py b/urls.py
index 4803171..38bc944 100644
--- a/urls.py
+++ b/urls.py
@@ -96,6 +96,14 @@ NOTE
 
 - The final _edit and CATCHALL also have to use re_path().
 
+(?P<thing>)
+This strange syntax is not a Django funny, it is standard (but obscure) python.
+It denotes a "Named Capturing Group" 
+https://docs.python.org/3/howto/regex.html#non-capturing-and-named-groups
+https://dnmtechs.com/understanding-the-django-regular-expression-p-in-python-3/
+https://www.regular-expressions.info/named.html
+e.g. the regular expression:
+r'^(?P<path>.*)/(?P<slug>[^/]+)_cave_edit/$'
 
 Many of these patterns do not work because troggle spent many years broken and we have
 not yet restored all the functions. Some may have never been fully implemented in