Merge pull request #147 from j08lue/master

new suggestion for addcyclic

Author: Jeff Whitaker

Changelog

@@ -1,7 +1,7 @@
 version 1.0.8 (not yet released)
 --------------------------------
 * don't assume grid is regular with adding cyclic point in addcyclic. 
-  New kwarg 'cyclic_dimension' added, with a default of 360.  Partially
+  New kwarg 'cyclic' added, with a default of 360.  Partially
   addresses issue 139.
 * fix for coastline drawing glitch (issue 123).
 * update shapefile.py to version 1.2.0 from pyshp.googlecode.com. Add back

README.md

@@ -108,4 +108,4 @@ Jeff Whitaker <[email protected]>
 
 ##Thanks
 
-Special thanks to John Hunter, Andrew Straw, Eric Firing, Rob Hetland, Scott Sinclair, Ivan Lima, Erik Andersen, Michael Hearne, Jesper Larsen, Ryan May, David Huard, Mauro Cavalcanti, Chris Murphy, Pierre Gerard-Marchant, Christoph Gohlke, Eric Bruning, Stephane Raynaud, Tom Loredo, Patrick Marsh, Phil Elson, and Henry Hammond for valuable contributions.
+Special thanks to John Hunter, Andrew Straw, Eric Firing, Rob Hetland, Scott Sinclair, Ivan Lima, Erik Andersen, Michael Hearne, Jesper Larsen, Ryan May, David Huard, Mauro Cavalcanti, Jonas Bluethgen, Chris Murphy, Pierre Gerard-Marchant, Christoph Gohlke, Eric Bruning, Stephane Raynaud, Tom Loredo, Patrick Marsh, Phil Elson, and Henry Hammond for valuable contributions.

lib/mpl_toolkits/basemap/__init__.py

@@ -5087,32 +5087,49 @@ def shiftgrid(lon0,datain,lonsin,start=True,cyclic=360.0):
     dataout[...,i0_shift:] = datain[...,start_idx:i0+start_idx]
     return dataout,lonsout
 
-def addcyclic(arrin,lonsin,cyclic_length=360):
+def addcyclic(*arr,**kwargs):
     """
-    ``arrout, lonsout = addcyclic(arrin, lonsin)``
-    adds cyclic (wraparound) point in longitude to ``arrin`` and ``lonsin``,
-    assumes longitude is the right-most dimension of ``arrin``.
-    If length of cyclic dimension is not 360 (degrees), set with kwarg
-    ``cyclic_length``.
+    Adds cyclic (wraparound) points in longitude to one or several arrays, 
+    the last array being longitudes in degrees. E.g.
+
+   ``data1out, data2out, lonsout = addcyclic(data1,data2,lons)``
+
+    ==============   ====================================================
+    Keywords         Description
+    ==============   ====================================================
+    axis             the dimension longitude is in (default right-most)
+    cyclic           width of periodic domain (default 360)
+    ==============   ====================================================
     """
-    nlons = arrin.shape[-1]
-    newshape = list(arrin.shape)
-    newshape[-1] += 1
-    if ma.isMA(arrin):
-        arrout  = ma.zeros(newshape,arrin.dtype)
-    else:
-        arrout  = np.zeros(newshape,arrin.dtype)
-    arrout[...,0:nlons] = arrin[:]
-    arrout[...,nlons] = arrin[...,0]
-    if ma.isMA(lonsin):
-        lonsout = ma.zeros(nlons+1,lonsin.dtype)
+    # get (default) keyword arguments
+    axis = kwargs.get('axis',-1)
+    cyclic = kwargs.get('cyclic',360)
+    # define functions
+    def _addcyclic(a):
+        """addcyclic function for a single data array"""
+        npsel = np.ma if np.ma.is_masked(a) else np
+        slicer = [slice(None)] * np.ndim(a)
+        try:
+            slicer[axis] = slice(0, 1)
+        except IndexError:
+            raise ValueError('The specified axis does not correspond to an '
+                    'array dimension.')
+        return npsel.concatenate((a,a[slicer]),axis=axis)
+    def _addcyclic_lon(a):
+        """addcyclic function for a single longitude array"""
+        # select the right numpy functions
+        npsel = np.ma if np.ma.is_masked(a) else np
+        # get cyclic longitudes
+        clon = (np.take(a,[0],axis=axis) 
+                + cyclic * np.sign(np.diff(np.take(a,[0,-1],axis=axis),axis=axis)))
+        # ensure the values do not exceed cyclic
+        clonmod = npsel.where(clon<=cyclic,clon,np.mod(clon,cyclic))
+        return npsel.concatenate((a,clonmod),axis=axis)
+    # process array(s)
+    if len(arr) == 1:
+        return _addcyclic_lon(arr[-1])
     else:
-        lonsout = np.zeros(nlons+1,lonsin.dtype)
-    lonsout[0:nlons] = lonsin[:]
-    # this assumes a regular grid (in longitude)
-    #lonsout[nlons]  = lonsin[-1] + lonsin[1]-lonsin[0]
-    # the version below is valid for irregular grids.
-    lonsout[nlons] = lonsin[-1] + cyclic_length % (lonsin[-1]-lonsin[0])
+        return map(_addcyclic,arr[:-1]) + [_addcyclic_lon(arr[-1])]
 
 def _choosecorners(width,height,**kwargs):
     """