Merge pull request #254 from matkoniecz/patch-1

fix typo

doc/ref_index.rst

@@ -11,7 +11,7 @@ Node Location Storage
 Node location can be cached in a ``LocationTable``. There are different
 implementations available which should be choosen according to the size of
 data and whether or not the cache should be permanent. See the Osmium manual
-for a detailed explaination. The compiled in types can be listed with the
+for a detailed explanation. The compiled in types can be listed with the
 ``map_types`` function, new stores can be created with ``create_map``.
 
 .. autofunction:: osmium.index.map_types