def __getattr__(self, key):
"""Return a grib key, or one of our extra keys."""
# is it in the grib message?
try:
# we just get <type 'float'> as the type of the "values" array...special case here...
if key in ["values", "pv", "latitudes", "longitudes"]:
res = gribapi.grib_get_double_array(self.grib_message, key)
elif key in ('typeOfFirstFixedSurface', 'typeOfSecondFixedSurface'):
res = np.int32(gribapi.grib_get_long(self.grib_message, key))
else:
key_type = gribapi.grib_get_native_type(self.grib_message, key)
if key_type == int:
res = np.int32(gribapi.grib_get_long(self.grib_message, key))
elif key_type == float:
# Because some computer keys are floats, like
# longitudeOfFirstGridPointInDegrees, a float32 is not always enough...
res = np.float64(gribapi.grib_get_double(self.grib_message, key))
elif key_type == str:
res = gribapi.grib_get_string(self.grib_message, key)
else:
raise ValueError("Unknown type for %s : %s" % (key, str(key_type)))
except gribapi.GribInternalError:
res = None
#...or is it in our list of extras?
if res is None:
if key in self.extra_keys:
res = self.extra_keys[key]
else:
#must raise an exception for the hasattr() mechanism to work
raise AttributeError("Cannot find GRIB key %s" % key)
return res
def __getattr__(self, key):
"""Return a grib key, or one of our extra keys."""
# is it in the grib message?
try:
# we just get <type 'float'> as the type of the "values" array...special case here...
if key in ["values", "pv", "latitudes", "longitudes"]:
res = gribapi.grib_get_double_array(self.grib_message, key)
elif key in ('typeOfFirstFixedSurface', 'typeOfSecondFixedSurface'):
res = np.int32(gribapi.grib_get_long(self.grib_message, key))
else:
key_type = gribapi.grib_get_native_type(self.grib_message, key)
if key_type == int:
res = np.int32(gribapi.grib_get_long(self.grib_message, key))
elif key_type == float:
# Because some computer keys are floats, like
# longitudeOfFirstGridPointInDegrees, a float32 is not always enough...
res = np.float64(gribapi.grib_get_double(self.grib_message, key))
elif key_type == str:
res = gribapi.grib_get_string(self.grib_message, key)
else:
raise ValueError("Unknown type for %s : %s" % (key, str(key_type)))
except gribapi.GribInternalError:
res = None
#...or is it in our list of extras?
if res is None:
if key in self.extra_keys:
res = self.extra_keys[key]
else:
#must raise an exception for the hasattr() mechanism to work
raise AttributeError("Cannot find GRIB key %s" % key)
return res
def grid_definition_template_12(cube, grib):
"""
Set keys within the provided grib message based on
Grid Definition Template 3.12.
Template 3.12 is used to represent a Transverse Mercator grid.
"""
gribapi.grib_set(grib, "gridDefinitionTemplateNumber", 12)
# Retrieve some information from the cube.
y_coord = cube.coord(dimensions=[0])
x_coord = cube.coord(dimensions=[1])
cs = y_coord.coord_system
# Normalise the coordinate values to centimetres - the resolution
# used in the GRIB message.
def points_in_cm(coord):
points = coord.units.convert(coord.points, 'cm')
points = np.around(points).astype(int)
return points
y_cm = points_in_cm(y_coord)
x_cm = points_in_cm(x_coord)
# Set some keys specific to GDT12.
# Encode the horizontal points.
# NB. Since we're already in centimetres, our tolerance for
# discrepancy in the differences is 1.
def step(points):
diffs = points[1:] - points[:-1]
mean_diff = np.mean(diffs).astype(points.dtype)
if not np.allclose(diffs, mean_diff, atol=1):
msg = ('Irregular coordinates not supported for transverse '
'Mercator.')
raise iris.exceptions.TranslationError(msg)
return int(mean_diff)
gribapi.grib_set(grib, 'Di', abs(step(x_cm)))
gribapi.grib_set(grib, 'Dj', abs(step(y_cm)))
horizontal_grid_common(cube, grib)
# GRIBAPI expects unsigned ints in X1, X2, Y1, Y2 but it should accept
# signed ints, so work around this.
# See https://software.ecmwf.int/issues/browse/SUP-1101
ensure_set_int32_value(grib, 'Y1', int(y_cm[0]))
ensure_set_int32_value(grib, 'Y2', int(y_cm[-1]))
ensure_set_int32_value(grib, 'X1', int(x_cm[0]))
ensure_set_int32_value(grib, 'X2', int(x_cm[-1]))
# Lat and lon of reference point are measured in millionths of a degree.
gribapi.grib_set(grib, "latitudeOfReferencePoint",
cs.latitude_of_projection_origin / _DEFAULT_DEGREES_UNITS)
gribapi.grib_set(grib, "longitudeOfReferencePoint",
cs.longitude_of_central_meridian / _DEFAULT_DEGREES_UNITS)
# Convert a value in metres into the closest integer number of
# centimetres.
def m_to_cm(value):
return int(round(value * 100))
# False easting and false northing are measured in units of (10^-2)m.
gribapi.grib_set(grib, 'XR', m_to_cm(cs.false_easting))
gribapi.grib_set(grib, 'YR', m_to_cm(cs.false_northing))
# GRIBAPI expects a signed int for scaleFactorAtReferencePoint
# but it should accept a float, so work around this.
# See https://software.ecmwf.int/issues/browse/SUP-1100
value = cs.scale_factor_at_central_meridian
key_type = gribapi.grib_get_native_type(grib,
"scaleFactorAtReferencePoint")
if key_type is not float:
value = fixup_float32_as_int32(value)
gribapi.grib_set(grib, "scaleFactorAtReferencePoint", value)
def grid_definition_template_12(cube, grib):
"""
Set keys within the provided grib message based on
Grid Definition Template 3.12.
Template 3.12 is used to represent a Transverse Mercator grid.
"""
gribapi.grib_set(grib, "gridDefinitionTemplateNumber", 12)
# Retrieve some information from the cube.
y_coord = cube.coord(dimensions=[0])
x_coord = cube.coord(dimensions=[1])
cs = y_coord.coord_system
# Normalise the coordinate values to centimetres - the resolution
# used in the GRIB message.
def points_in_cm(coord):
points = coord.units.convert(coord.points, 'cm')
points = np.around(points).astype(int)
return points
y_cm = points_in_cm(y_coord)
x_cm = points_in_cm(x_coord)
# Set some keys specific to GDT12.
# Encode the horizontal points.
# NB. Since we're already in centimetres, our tolerance for
# discrepancy in the differences is 1.
def step(points):
diffs = points[1:] - points[:-1]
mean_diff = np.mean(diffs).astype(points.dtype)
if not np.allclose(diffs, mean_diff, atol=1):
msg = ('Irregular coordinates not supported for transverse '
'Mercator.')
raise iris.exceptions.TranslationError(msg)
return int(mean_diff)
gribapi.grib_set(grib, 'Di', abs(step(x_cm)))
gribapi.grib_set(grib, 'Dj', abs(step(y_cm)))
horizontal_grid_common(cube, grib)
# GRIBAPI expects unsigned ints in X1, X2, Y1, Y2 but it should accept
# signed ints, so work around this.
# See https://software.ecmwf.int/issues/browse/SUP-1101
ensure_set_int32_value(grib, 'Y1', int(y_cm[0]))
ensure_set_int32_value(grib, 'Y2', int(y_cm[-1]))
ensure_set_int32_value(grib, 'X1', int(x_cm[0]))
ensure_set_int32_value(grib, 'X2', int(x_cm[-1]))
# Lat and lon of reference point are measured in millionths of a degree.
gribapi.grib_set(grib, "latitudeOfReferencePoint",
cs.latitude_of_projection_origin / _DEFAULT_DEGREES_UNITS)
gribapi.grib_set(grib, "longitudeOfReferencePoint",
cs.longitude_of_central_meridian / _DEFAULT_DEGREES_UNITS)
# Convert a value in metres into the closest integer number of
# centimetres.
def m_to_cm(value):
return int(round(value * 100))
# False easting and false northing are measured in units of (10^-2)m.
gribapi.grib_set(grib, 'XR', m_to_cm(cs.false_easting))
gribapi.grib_set(grib, 'YR', m_to_cm(cs.false_northing))
# GRIBAPI expects a signed int for scaleFactorAtReferencePoint
# but it should accept a float, so work around this.
# See https://software.ecmwf.int/issues/browse/SUP-1100
value = cs.scale_factor_at_central_meridian
key_type = gribapi.grib_get_native_type(grib,
"scaleFactorAtReferencePoint")
if key_type is not float:
value = fixup_float32_as_int32(value)
gribapi.grib_set(grib, "scaleFactorAtReferencePoint", value)
