Merge pull request #236 from jswhit/issue235

fix for issue #235 (latlons doesn't work if only 1 latitude in grid)

Author: jswhit

Changelog

@@ -3,6 +3,7 @@ version 2.1.6 (not yet released)
 * switch dynamic version handling from pkg_resources (in setuptools) to packaging
 * expose 'redtoreg' function for interpolating reduced to full gaussian
   gridded fields, optimize function for 50x speedup.
+* Fix for issue #235 (`latlons` doesn't work when only a single latitude in grid).
 
 version 2.1.5 release
 =====================

src/pygrib/_pygrib.pyx

@@ -1539,7 +1539,8 @@ cdef class gribmessage(object):
             lat1 = self['latitudeOfFirstGridPointInDegrees']
             lat2 = self['latitudeOfLastGridPointInDegrees']
             lats = self['distinctLatitudes']
-            if lat2 < lat1 and lats[-1] > lats[0]: lats = lats[::-1]
+            if self['Nj'] > 1:
+                if lat2 < lat1 and lats[-1] > lats[0]: lats = lats[::-1]
             lons = self['distinctLongitudes']
             lons,lats = np.meshgrid(lons,lats) 
         elif self['gridType'] == 'reduced_gg': # reduced global gaussian grid