added sketch for edges2vertex

pyicon/pyicon_calc_xr.py

@@ -416,6 +416,40 @@ def xr_edges2edges_via_cell(ds_IcD, vn_e, scalar, dze='const'):
     out_vn_e = ()
     return out_vn_e
 
+
+## Mapping between edges and vertices
+
+def xr_edges2vertex(ds_IcD, e_vector, dze, dzv, dAd, edge2vertex_coeff=None):
+    """ Maps edge vectors to vertices using equation 22 of Korn (2017)
+
+    Parameters
+    ----------
+    ds_IcD : xr.Dataset
+        pyicon dataset containing coordinate info
+
+    e_vector : xr.DataArray
+        Dataarray containing vector variable on cell edges.
+
+    dze : xr.DataArray
+        dz defined on edges
+
+    dzv : xr.DataArray
+        dz defined on vertices
+
+    edge2vertex_coeff : xr.DataArray or None
+        COMMENT
+
+    Returns
+    -------
+    vertex_vec : xr.DataArray
+        edge vector interpolated to the vertices
+
+    Notes
+    -----
+    This uses the formula defined in equation 22 of Korn (2017).
+    """
+    pass
+
 ## Divergence
 
 def xr_calc_div_coeff(ds_IcD):