def create_proj_group(filename: str, parent: TextIO, area_def):
"""Create the top level group from projection information."""
projection_name = (area_def.area_id).replace(" ", "_")
# if top group alrady made, return.
if projection_name in parent:
return projection_name
# create top group for first time
group = parent.create_group(projection_name)
# add attributes from grid_defintion.
if isinstance(area_def, SwathDefinition):
group.attrs["height"], group.attrs["width"] = area_def.shape
group.attrs["description"] = "No projection: native format"
else:
group.attrs["proj4_definition"] = area_def.proj4_string
for a in ["height", "width"]:
ds_attr = getattr(area_def, a, None)
if ds_attr is None:
pass
else:
group.attrs[a] = ds_attr
group.attrs["cell_height"] = np.round(-area_def.pixel_size_y, 5)
group.attrs["cell_width"] = np.round(area_def.pixel_size_x, 5)
group.attrs["origin_x"] = area_def.pixel_upper_left[0]
group.attrs["origin_y"] = area_def.pixel_upper_left[1]
return projection_name
