Hot fix get_dataarray_resolution (#162)

* res attribute can be an array

* get resolution: check if res attribute an array-like object

Author: thuydotm

xrspatial/utils.py

@@ -86,12 +86,9 @@ def calc_res(raster):
 
 def get_dataarray_resolution(agg: xr.DataArray):
 
-    if not agg.attrs.get('res'):
-        raise ValueError('input xarray must have `res` attr.')
-
     # get cellsize out from 'res' attribute
     cellsize = agg.attrs.get('res')
-    if isinstance(cellsize, tuple) and len(cellsize) == 2 \
+    if isinstance(cellsize, (tuple, np.ndarray, list)) and len(cellsize) == 2 \
             and isinstance(cellsize[0], (int, float)) \
             and isinstance(cellsize[1], (int, float)):
         cellsize_x, cellsize_y = cellsize