def contains(self, lon, lat):
""" Return a boolean array of same shape as lon and lat with points contained in the patch
"""
lon = np.asarray(lon)
lat = np.asarray(lat)
mlon, mlat = self.coords
assert lon.shape == lat.shape, "lon, lat must have the same shape"
#lon = rectify_longitude(lon, lon0=self.lon0, sort=False)
# first fix lon0 to match new data
lon0 = get_lon0(*lon.flatten())
if lon0 != self.lon0:
self = copy(self)
mlon, self.mask = rectify_longitude_data(mlon, self.mask, lon0)
if not (np.all(lon == mlon) and np.all(lat == mlat)):
self = copy(self)
# interpolate the mask onto the input grid
maskf = interp(np.asarray(self.mask, dtype=float), mlon, mlat, lon,
lat)
mask = maskf >= 0.5
else:
mask = self.mask
return mask
def contains(self, lon, lat):
""" Return a boolean array of same shape as lon and lat with points contained in the patch
"""
lon = np.asarray(lon)
lat = np.asarray(lat)
mlon, mlat = self.coords
assert lon.shape == lat.shape, "lon, lat must have the same shape"
#lon = rectify_longitude(lon, lon0=self.lon0, sort=False)
# first fix lon0 to match new data
lon0 = get_lon0(*lon.flatten())
if lon0 != self.lon0:
self = copy(self)
mlon, self.mask = rectify_longitude_data(mlon, self.mask, lon0)
if not (np.all(lon == mlon) and np.all(lat == mlat)):
self = copy(self)
# interpolate the mask onto the input grid
maskf = interp(np.asarray(self.mask, dtype=float), mlon, mlat, lon, lat)
mask = maskf >= 0.5
else:
mask = self.mask
return mask
def interp2(lon, lat, data, lon2, lat2, order=1):
""" Equivalent to matlab interp2
order:
- 0 : nearest neighbout
- 1 : linear (default)
"""
from dimarray.compat.basemap import interp
if np.ndim(lon2) == 1:
lon2, lat2 = np.meshgrid(lon2, lat2)
return interp(data, lon, lat, lon2, lat2, order=order)
def interp2(lon, lat, data, lon2, lat2, order=1):
""" Equivalent to matlab interp2
order:
- 0 : nearest neighbout
- 1 : linear (default)
"""
from dimarray.compat.basemap import interp
if np.ndim(lon2) == 1:
lon2, lat2 = np.meshgrid(lon2, lat2)
return interp(data, lon, lat, lon2, lat2, order=order)
def interpolate(self, lon, lat):
""" interpolate the mask
lon, lat: 1-D arrays to be passed to meshgrid
"""
assert lon.ndim == 1 and lat.ndim == 1, "must be 1-D coordinates compatible with meshgrid"
# first fix lon0 to match new data
lon0 = get_lon0(*lon.flatten())
mlon, mlat = self.coords
mlon, mask = rectify_longitude_data(mlon, self.mask, lon0)
# make input coords is 2-D
#if lon.ndim == 1 and meshgrid:
lon2, lat2 = np.meshgrid(lon, lat)
maskf = interp(np.asarray(self.mask, dtype=float), mlon, mlat, lon2, lat2)
mask = maskf >= 0.5
return Mask(lon, lat, mask, lon0)
def interpolate(self, lon, lat):
""" interpolate the mask
lon, lat: 1-D arrays to be passed to meshgrid
"""
assert lon.ndim == 1 and lat.ndim == 1, "must be 1-D coordinates compatible with meshgrid"
# first fix lon0 to match new data
lon0 = get_lon0(*lon.flatten())
mlon, mlat = self.coords
mlon, mask = rectify_longitude_data(mlon, self.mask, lon0)
# make input coords is 2-D
#if lon.ndim == 1 and meshgrid:
lon2, lat2 = np.meshgrid(lon, lat)
maskf = interp(np.asarray(self.mask, dtype=float), mlon, mlat, lon2,
lat2)
mask = maskf >= 0.5
return Mask(lon, lat, mask, lon0)
def interp2d(dim_array, newaxes, dims=(-2, -1), order=1, clip=False):
""" bilinear interpolation
Parameters
----------
dim_array : DimArray instance
newaxes : sequence of two array-like, or dict.
axes on which to interpolate
dims : sequence of two axis names or integer rank, optional
Indicate dimensions which match `newaxes`.
By default (-2, -1) (last two dimensions).
order : int, optional
order of the interpolation (default 1 for linear)
clip : bool, optional
if True, values in newaxes outside the range are clipped to closest
values
Returns
-------
dim_array_int : DimArray instance
interpolated array
Examples
--------
>>> from dimarray import DimArray, interp2d
>>> x = np.array([0, 1, 2])
>>> y = np.array([0, 10])
>>> a = DimArray([[0,0,1],[1,0.,0.]], [('y',y),('x',x)])
>>> a
dimarray: 6 non-null elements (0 null)
0 / y (2): 0 to 10
1 / x (3): 0 to 2
array([[ 0., 0., 1.],
[ 1., 0., 0.]])
>>> newx = [0.5, 1.5]
>>> newy = np.linspace(0,10,5)
>>> ai = interp2d(a, [newy, newx])
>>> ai
dimarray: 10 non-null elements (0 null)
0 / y (5): 0.0 to 10.0
1 / x (2): 0.5 to 1.5
array([[ 0. , 0.5 ],
[ 0.125, 0.375],
[ 0.25 , 0.25 ],
[ 0.375, 0.125],
[ 0.5 , 0. ]])
Use dims keyword argument if new axes order does not match array dimensions
>>> (ai == interp2d(a, [newx, newy], dims=('x','y'))).all()
True
>>> newx = [-1, 1]
>>> newy = [-5, 0, 10]
>>> interp2d(a, [newy, newx])
dimarray: 2 non-null elements (4 null)
0 / y (3): -5 to 10
1 / x (2): -1 to 1
array([[ nan, nan],
[ nan, 0.],
[ nan, 0.]])
>>> interp2d(a, [newy, newx], clip=True)
dimarray: 6 non-null elements (0 null)
0 / y (3): -5 to 10
1 / x (2): -1 to 1
array([[ 0., 0.],
[ 0., 0.],
[ 1., 0.]])
"""
# provided as a dictionary
if isinstance(newaxes, dict):
dims = newaxes.keys()
newaxes = newaxes.values()
if not isinstance(newaxes, list) or isinstance(newaxes, tuple):
raise TypeError("newaxes must be a sequence of axes to interpolate on")
if len(newaxes) != 2:
raise ValueError("must provide two axis values to interpolate on")
if len(dims) != 2:
raise ValueError("must provide two axis names to interpolate on")
x0 = dim_array.axes[dims[0]]
y0 = dim_array.axes[dims[1]]
# new axes
xi, yi = newaxes
xi2, yi2 = np.meshgrid(xi, yi) # requires 2-D grid
xi = Axis(xi, x0.name) # convert to Axis
yi = Axis(yi, y0.name)
# transpose the array to shape .., y0, x0 (cartesian convention needed for interp)
dims_orig = dim_array.dims
dims_new = [d for d in dim_array.dims if d not in [x0.name, y0.name]] + [y0.name, x0.name]
dim_array = dim_array.transpose(dims_new)
if dim_array.ndim == 2:
newvalues = interp(dim_array.values, x0.values, y0.values, xi2, yi2, masked=not clip)
dim_array_int = dim_array._constructor(newvalues, [yi, xi])
else:
# first reshape to 3-D, flattening everything except horizontal_coordinates coordinates
# TODO: optimize by computing and re-using weights?
dim_array = dim_array.group((x0.name, y0.name), reverse=True, insert=0)
newvalues = []
for k, suba in dim_array.iter(axis=0): # iterate over the first dimension
newval = interp(suba.values, x0.values, y0.values, xi2, yi2, masked=not clip)
newvalues.append(newval)
# stack the arrays together
newvalues = np.array(newvalues)
grouped_dim_array = dim_array._constructor(newvalues, [dim_array.axes[0], yi, xi])
dim_array_int = grouped_dim_array.ungroup(axis=0)
# reshape back
# ...replace old axis names by new ones of the projection
dims_orig = list(dims_orig)
# ...transpose
dim_array_int = dim_array_int.transpose(dims_orig)
# add metadata
dim_array_int._metadata(dim_array._metadata())
return dim_array_int
def transform_vectors(u, v, to_crs, from_crs=None, \
xt=None, yt=None, masked=np.nan):
""" Transform vector field array into a new coordinate system and \
interpolate values onto a new regular grid
Assume the vector field is represented by an array of shape (2, Ny, Nx)
Parameters
----------
u, v : GeoArray or other DimArray instances
x- and y- vector components
to_crs : str or dict or cartopy.crs.CRS instance
grid mapping onto which the transformation should be done
str : PROJ.4 str or cartopy.crs.CRS class name
dict : CF parameters
from_crs : idem, optional
original grid mapping. Can be omitted if the grid_mapping attribute
already contains the appropriate information, or if the horizontal
coordinates are longitude and latitude.
xt, yt : array-like (1-D), optional
new coordinates to interpolate the array on
will be deduced as min and max of new coordinates if not provided
masked : bool or number, optional
If False, interpolated values outside the range of input grid
will be clipped to values on boundary of input grid
If True, points outside the range of input grid
are masked (set to NaN)
If masked is set to a number, then
points outside the range of xin and yin will be
set to that number.
Default is nan.
Returns
-------
transformed : GeoArray
new 3-D GeoArray transformed and interpolated
"""
if not isinstance(u, DimArray) or not isinstance(v, DimArray):
raise TypeError("u and v must be DimArray instances")
if not isinstance(u, GeoArray):
u = GeoArray(u)
if not isinstance(v, GeoArray):
v = GeoArray(v)
# consistency check between u and v
assert u.axes == v.axes , "u and v must have the same axes"
if from_crs is None and hasattr(u, 'grid_mapping'):
assert hasattr(v, 'grid_mapping') and u.grid_mapping == v.grid_mapping, 'u and v must have the same grid mapping'
# get grid mapping instances
from_crs = _get_crs(from_crs, u)
to_crs = _get_crs(to_crs)
# find horizontal coordinates
x0, y0 = _check_horizontal_coordinates(u)
# Transform coordinates and prepare regular grid for interpolation
x0_interp, y0_interp, xt, yt = _inverse_transform_coords(from_crs, to_crs, xt, yt, x0, y0)
# Transform vector components
x0_2d, y0_2d = np.meshgrid(x0, y0)
if masked is True:
masked = np.nan # use NaN instead of MaskedArray
_constructor = u._constructor
if u.ndim == 2:
# First transform vector components onto the new coordinate system
_ut, _vt = to_crs.transform_vectors(from_crs, x0_2d, y0_2d, u.values, v.values)
# Then interpolate onto regular grid
_ui = interp(_ut, x0.values, y0.values, x0_interp, y0_interp, masked=masked)
ut = _constructor(_ui, [yt, xt])
_vi = interp(_vt, x0.values, y0.values, x0_interp, y0_interp, masked=masked)
vt = _constructor(_vi, [yt, xt])
else:
# first reshape to 3-D components, flattening everything except horizontal coordinates
# TODO: optimize by computing and re-using weights?
obj = stack([u, v], axis='vector_components', keys=['u','v'])
obj = obj.group(('vector_components', x0.name, y0.name), reverse=True, insert=0) #
newvalues = []
for k, suba in obj.iter(axis=0): # iterate over the first dimension
# First transform vector components onto the new coordinate system
_ut, _vt = to_crs.transform_vectors(from_crs, x0_2d, y0_2d, suba.values[0], suba.values[1])
# Then interpolate onto regular grid
_ui = interp(_ut, x0.values, y0.values, x0_interp, y0_interp, masked=masked)
_vi = interp(_vt, x0.values, y0.values, x0_interp, y0_interp, masked=masked)
newvalues.append(np.array([_ui, _vi]))
# stack the arrays together
newvalues = np.array(newvalues) # 4-D : grouped, vector_components, y, x
grouped_obj = _constructor(newvalues, [obj.axes[0], obj.axes[1], yt, xt])
ut, vt = grouped_obj.ungroup(axis=0).swapaxes('vector_components',0)
# add metadata
ut._metadata(u._metadata())
vt._metadata(v._metadata())
_add_grid_mapping_metadata(ut, to_crs)
_add_grid_mapping_metadata(vt, to_crs)
return ut, vt
def transform(geo_array, to_crs, from_crs=None, \
xt=None, yt=None, masked=np.nan):
""" Transform scalar field array into a new coordinate system and \
interpolate values onto a new regular grid
Parameters
----------
geo_array : GeoArray or other DimArray instance
to_crs : str or dict or cartopy.crs.CRS instance
grid mapping onto which the transformation should be done
str : PROJ.4 str or cartopy.crs.CRS class name
dict : CF parameters
from_crs : idem, optional
original grid mapping. Can be omitted if the grid_mapping attribute
already contains the appropriate information, or if the horizontal
coordinates are longitude and latitude.
xt, yt : array-like (1-D), optional
new coordinates to interpolate the array on
will be deduced as min and max of new coordinates if not provided
masked : bool or number, optional
If False, interpolated values outside the range of input grid
will be clipped to values on boundary of input grid
If True, points outside the range of input grid
are set to NaN
If masked is set to a number, then
points outside the range of xin and yin will be
set to that number.
Default is nan.
Returns
-------
transformed : GeoArray
new GeoArray transformed
Attempt is made to document the projection with CF-conform metadata
Examples
--------
"""
# local import since it's quite heavy
if not isinstance(geo_array, DimArray):
raise TypeError("geo_array must be a DimArray instance")
if not isinstance(geo_array, GeoArray):
geo_array = GeoArray(geo_array)
# find horizontal coordinates
x0, y0 = _check_horizontal_coordinates(geo_array)
# transpose the array to shape .., y0, x0 (cartesian convention needed for meshgrid)
dims_orig = geo_array.dims
dims_new = [d for d in geo_array.dims if d not in [x0.name, y0.name]] + [y0.name, x0.name]
geo_array = geo_array.transpose(dims_new)
#assert geo_array.dims.index(x0.name) > geo_array.axes[
# get cartopy.crs.CRS instances
from_crs = _get_crs(from_crs, geo_array)
to_crs = _get_crs(to_crs)
# Transform coordinates and prepare regular grid for interpolation
x0_interp, y0_interp, xt, yt = _inverse_transform_coords(from_crs, to_crs, xt, yt, x0, y0)
if masked is True:
masked = np.nan # use NaN instead of MaskedArray
if geo_array.ndim == 2:
#newvalues = interp(geo_array.values, xt_2d, yt_2d, xt_2dr, yt_2dr)
newvalues = interp(geo_array.values, x0.values, y0.values, x0_interp, y0_interp, masked=masked)
transformed = geo_array._constructor(newvalues, [yt, xt])
else:
# first reshape to 3-D, flattening everything except horizontal_coordinates coordinates
# TODO: optimize by computing and re-using weights?
obj = geo_array.group((x0.name, y0.name), reverse=True, insert=0)
newvalues = []
for k, suba in obj.iter(axis=0): # iterate over the first dimension
#newval = interp(suba.values, xt_2d, yt_2d, xt_2dr, yt_2dr)
newval = interp(suba.values, x0.values, y0.values, x0_interp, y0_interp, masked=masked)
newvalues.append(newval)
# stack the arrays together
newvalues = np.array(newvalues)
grouped_obj = geo_array._constructor(newvalues, [obj.axes[0], yt, xt])
transformed = grouped_obj.ungroup(axis=0)
# reshape back
# ...replace old axis names by new ones of the projection
dims_orig = list(dims_orig)
dims_orig[dims_orig.index(x0.name)] = xt.name
dims_orig[dims_orig.index(y0.name)] = yt.name
# ...transpose
transformed = transformed.transpose(dims_orig)
# add metadata
transformed._metadata(geo_array._metadata())
_add_grid_mapping_metadata(transformed, to_crs)
return transformed
def interp2d(obj, order=1):
""" 2-D interpolation function appled recursively on the object
"""
x0, y0 = obj.axes[x.name].values, obj.axes[y.name].values
res = interp(obj.values, x0, y0, x1, y1, order=order)
return obj._constructor(res, newaxes, **obj._metadata)
def interp2d(obj, order=1):
""" 2-D interpolation function appled recursively on the object
"""
x0, y0 = obj.axes[x.name].values, obj.axes[y.name].values
res = interp(obj.values, x0, y0, x1, y1, order=order)
return obj._constructor(res, newaxes, **obj._metadata)
