Add to documentation

Author: seisman

doc/api/index.rst

@@ -197,6 +197,17 @@ Getting metadata from tabular or grid data:
     info
     grdinfo
 
+Common Parameters
+-----------------
+
+.. currentmodule:: pygmt.params
+
+.. autosummary::
+    :toctree: generated
+    
+    Box
+    Frame
+
 Enums
 -----