DOCS-3338 added note about sort order to $near and geoNear.

source/core/2dsphere.txt

@@ -172,6 +172,11 @@ coordinate pair with the ``[ 0 , 0 ]`` coordinate:
        }
    }
 
+For Polygons with a single ring:
+
+- The ring cannot self-intersect.
+
+
 For Polygons with multiple rings:
 
 - The first described ring must be the exterior ring.

source/reference/command/geoNear.txt

@@ -16,6 +16,15 @@ Definition
    of :query:`$near`, :dbcommand:`geoNear` returns additional
    diagnostic information.
 
+   .. note::
+
+   The :dbcommand:`geoNear` always returns the documents sorted by distance.
+   Any other sort order requires to sort the documents in memory, which can
+   be inefficient. If another sort order is desired, use the 
+   :operator:`$geoWithin` operator in combination with :method:`sort()` 
+   instead.  
+
+
    The :dbcommand:`geoNear` command can use either a :term:`GeoJSON`
    point or :term:`legacy coordinate pairs`. Queries that use a ``2d``
    index return a limit of 100 documents.

source/reference/operator/query/near.txt

@@ -12,6 +12,15 @@ $near
    closest documents first. The query sorts the documents from nearest
    to farthest.
 
+   .. note::
+
+   The :dbcommand:`geoNear` always returns the documents sorted by distance.
+   Any other sort order requires to sort the documents in memory, which can
+   be inefficient. If another sort order is desired, use the 
+   :operator:`$geoWithin` operator in combination with :method:`sort()` 
+   instead.  
+
+
    The :query:`$near` operator can query for a :term:`GeoJSON`
    point or for a point defined by legacy coordinate pairs.