def GLDAS025Grids(only_land=False):
"""
Create global 0.25 DEG gldas grids (origin in bottom left)
Parameters
---------
only_land : bool, optional (default: False)
Uses the land mask to reduce the GLDAS 0.25DEG land grid to land points
only.
Returns
--------
grid : pygeogrids.CellGrid
Either a land grid or a global grid
"""
resolution = 0.25
glob_lons = np.arange(-180 + resolution / 2, 180 + resolution / 2,
resolution)
glob_lats = np.arange(-90 + resolution / 2, 90 + resolution / 2,
resolution)
lon, lat = np.meshgrid(glob_lons, glob_lats)
glob_grid = BasicGrid(lon.flatten(),
lat.flatten()).to_cell_grid(cellsize=5.0)
if only_land:
ds = Dataset(
os.path.join(
os.path.abspath(os.path.dirname(__file__)),
"GLDASp4_landmask_025d.nc4",
))
land_lats = ds.variables["lat"][:]
land_mask = ds.variables["GLDAS_mask"][:].flatten().filled() == 0.0
dlat = glob_lats.size - land_lats.size
land_mask = np.concatenate((np.ones(dlat * glob_lons.size), land_mask))
land_points = np.ma.masked_array(glob_grid.get_grid_points()[0],
land_mask)
land_grid = glob_grid.subgrid_from_gpis(
land_points[~land_points.mask].filled())
return land_grid
else:
return glob_grid
def __init__(
self,
filename_pattern,
parameter="mrsos",
cellsize=5.0,
only_land=False,
bbox=None,
):
self.parameter = parameter
self.cellsize = cellsize
self.only_land = only_land
# open dataset with xarray, using dask backend for parallel access
ds = xr.open_mfdataset(
str(filename_pattern), parallel=True, concat_dim="time"
)
self.dataset = ds.stack(dimensions={"latlon": ("lat", "lon")})
# lons are between 0 and 360, they have to be remapped to (-180, 180)
self._lons = np.array(self.dataset.lon.values)
self._lons[self._lons > 180] -= 360
# setup grid
global_grid = BasicGrid(self.lon, self.lat)
# land mask
self.landmask = ~np.isnan(self.dataset[parameter].isel(time=0).values)
self.land_gpis = global_grid.get_grid_points()[0][self.landmask]
if self.only_land:
grid = global_grid.subgrid_from_gpis(self.land_gpis)
else:
grid = global_grid
# bounding box
if bbox is not None:
# given is: bbox = [lonmin, latmin, lonmax, latmax]
self.lonmin, self.latmin, self.lonmax, self.latmax = (*bbox,)
self.bbox_gpis = grid.get_bbox_grid_points(
lonmin=self.lonmin,
latmin=self.latmin,
lonmax=self.lonmax,
latmax=self.latmax,
)
grid = grid.subgrid_from_gpis(self.bbox_gpis)
self.grid = grid.to_cell_grid(cellsize=self.cellsize)
print(f"Number of active gpis: {len(self.grid.activegpis)}")
print(f"Number of grid cells: {len(self.grid.get_cells())}")
# create metadata dictionary from dataset attributes
self.metadata = copy(self.dataset.attrs)
array_metadata = copy(self.dataset[self.parameter].attrs)
# merging history metadata (the only common keyword)
self.metadata["history"] = (
"Dataset: "
+ self.metadata["history"]
+ "; DataArray: "
+ array_metadata["history"]
)
del array_metadata["history"]
self.metadata.update(array_metadata)
def __init__(
self,
fname,
parameters,
loading_func,
cellsize=5.0,
only_land=False,
bbox=None,
):
# input validation
if isinstance(parameters, str):
parameters = [parameters]
self.parameters = parameters
if isinstance(loading_func, str):
if loading_func not in loading_func_dict: # pragma: no cover
raise ValueError(
f"No loading function with the name '{loading_func}'"
" exists.")
loading_func = loading_func_dict[loading_func]
self.loading_func = loading_func
self.cellsize = cellsize
self.only_land = only_land
# load dataset
self.dataset = loading_func(str(fname), self.parameters)
# Img2Ts prefers flattened data
self.dataset = self.dataset.stack(
dimensions={"latlon": ("lat", "lon")})
# lons are between 0 and 360, they have to be remapped to (-180, 180)
self._lons = np.array(self.dataset.lon.values)
self._lons[self._lons > 180] -= 360
# setup grid
global_grid = BasicGrid(self.lon, self.lat)
# land mask
if self.only_land:
if "landmask" in self.dataset:
self.landmask = self.dataset.landmask.values
else: # pragma: no cover
raise ValueError("No landmask available!")
self.land_gpis = global_grid.get_grid_points()[0][self.landmask]
grid = global_grid.subgrid_from_gpis(self.land_gpis)
else:
grid = global_grid
# bounding box
if bbox is not None:
# given is: bbox = [lonmin, latmin, lonmax, latmax]
self.lonmin, self.latmin, self.lonmax, self.latmax = (*bbox, )
self.bbox_gpis = grid.get_bbox_grid_points(
lonmin=self.lonmin,
latmin=self.latmin,
lonmax=self.lonmax,
latmax=self.latmax,
)
grid = grid.subgrid_from_gpis(self.bbox_gpis)
self.grid = grid.to_cell_grid(cellsize=self.cellsize)
print(f"Number of active gpis: {len(self.grid.activegpis)}")
print(f"Number of grid cells: {len(self.grid.get_cells())}")
# create metadata dictionary from dataset attributes
# this copies the dataset metadata directly and appends metadata of the
# single variables with <param_name>_ as prefix to their metadata keys.
self.metadata = copy(self.dataset.attrs)
array_metadata = {}
for p in self.parameters:
md = copy(self.dataset[p].attrs)
for key in md:
array_metadata["_".join([p, key])] = md[key]
self.metadata.update(array_metadata)
