Add support for data

Author: rhattersley

lib/iris/fileformats/grib/_message.py

@@ -101,7 +101,7 @@ def data(self):
                                    'unsupported quasi-regular grid.')
 
         template = grid_section['gridDefinitionTemplateNumber']
-        if template in (0, 1, 5, 90):
+        if template in (0, 1, 5, 12, 90):
             # We can ignore the first two bits (i-neg, j-pos) because
             # that is already captured in the coordinate values.
             if grid_section['scanningMode'] & 0x3f:

lib/iris/tests/unit/fileformats/grib/message/test__GribMessage.py

@@ -214,6 +214,11 @@ def section_3(self, scanning_mode):
         return _example_section_3(5, scanning_mode)
 
 
+class Test_data__grid_template_12(tests.IrisTest, Mixin_data__grid_template):
+    def section_3(self, scanning_mode):
+        return _example_section_3(12, scanning_mode)
+
+
 class Test_data__grid_template_90(tests.IrisTest, Mixin_data__grid_template):
     def section_3(self, scanning_mode):
         section_3 = _example_section_3(90, scanning_mode)