diff --git a/doc/rst/source/explain_-L_scale.rst_ b/doc/rst/source/explain_-L_scale.rst_
index e52b662d1ca..306fb8b3771 100644
--- a/doc/rst/source/explain_-L_scale.rst_
+++ b/doc/rst/source/explain_-L_scale.rst_
@@ -18,7 +18,7 @@
     - **+w**\ *length* to set scale *length* in km, or append :ref:`unit <tbl-distunits>` from
       **e**\|\ **f**\|\ **k**\|\ **M**\|\ **n**\|\ **u**.
     - **+a**\ *align* to change the label alignment (choose among **l**\ (eft), **r**\ (ight), **t**\ (op), and
-      **b**\ (ottom)) [default is **t**\ (op)].
+      **b**\ (ottom)) [default is **t**\ (op) for horizontal scale and **r**\ (ight) for vertical scale].
     - **+c**\ [[*slon*/]\ *slat*] to control where on a geographic map the scale applies. Map scale is calculated for
       latitude *slat* (optionally supply longitude *slon* for oblique projections [default is central meridian]). If
       **+c** is not given we default to the location of the *refpoint*. If **+c** is given with no arguments then we