Fixed issue #1520, by adding a if-else that checks for None (#1526)

* Fixed issue #1520, by adding a if-else that checks for None

* Changed the read_rasterio to skip CRS entirely if it is None

* Added whats new comment on fix of issue #1520

* Resolved a conflict with master branch.

* Deleted a line change from whats new

Author: leeviannala

doc/whats-new.rst

@@ -120,6 +120,10 @@ Bug fixes
   objects with data stored as ``dask`` arrays (:issue:`1529`).
   By `Joe Hamman <https://github.com/jhamman>`_.
 
+- :py:func:`~xarray.open_rasterio` method now skips rasterio.crs -attribute if
+  it is none.
+  By `Leevi Annala <https://github.com/leevei>`_.
+
 .. _whats-new.0.9.6:
 
 v0.9.6 (8 June 2017)
@@ -2028,4 +2032,4 @@ Miles.
 v0.1 (2 May 2014)
 -----------------
 
-Initial release.
+Initial release.

xarray/backends/rasterio_.py

@@ -142,9 +142,10 @@ def open_rasterio(filename, chunks=None, cache=None, lock=None):
 
     # Attributes
     attrs = {}
-    if hasattr(riods, 'crs'):
+    if hasattr(riods, 'crs') and riods.crs:
         # CRS is a dict-like object specific to rasterio
-        # We convert it back to a PROJ4 string using rasterio itself
+        # If CRS is not None, we convert it back to a PROJ4 string using
+        # rasterio itself
         attrs['crs'] = riods.crs.to_string()
     if hasattr(riods, 'res'):
         # (width, height) tuple of pixels in units of CRS