def extract_GOT_constants(ilon,
ilat,
model_files,
METHOD=None,
EXTRAPOLATE=False,
GZIP=True,
SCALE=1.0):
"""
Reads files for Richard Ray's Global Ocean Tide (GOT) models
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Arguments
---------
ilon: longitude to interpolate
ilat: latitude to interpolate
model_files: list of model files for each constituent
Keyword arguments
-----------------
METHOD: interpolation method
bilinear: quick bilinear interpolation
spline: scipy bivariate spline interpolation
linear, nearest: scipy regular grid interpolations
EXTRAPOLATE: extrapolate model using nearest-neighbors
GZIP: input files are compressed
SCALE: scaling factor for converting to output units
Returns
-------
amplitude: amplitudes of tidal constituents
phase: phases of tidal constituents
constituents: list of model constituents
"""
#-- adjust dimensions of input coordinates to be iterable
ilon = np.atleast_1d(ilon)
ilat = np.atleast_1d(ilat)
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
if (np.min(ilon) < 0.0):
lt0, = np.nonzero(ilon < 0)
ilon[lt0] += 360.0
#-- number of points
npts = len(ilon)
#-- amplitude and phase
constituents = []
nc = len(model_files)
amplitude = np.ma.zeros((npts, nc))
amplitude.mask = np.zeros((npts, nc), dtype=bool)
ph = np.ma.zeros((npts, nc))
ph.mask = np.zeros((npts, nc), dtype=bool)
#-- read and interpolate each constituent
for i, model_file in enumerate(model_files):
#-- read constituent from elevation file
hc, lon, lat, cons = read_GOT_grid(os.path.expanduser(model_file),
GZIP=GZIP)
#-- append to the list of constituents
constituents.append(cons)
#-- grid step size of tide model
dlon = np.abs(lon[1] - lon[0])
dlat = np.abs(lat[1] - lat[0])
#-- replace original values with extend matrices
lon = extend_array(lon, dlon)
hc = extend_matrix(hc)
#-- interpolated complex form of constituent oscillation
hci = np.ma.zeros((npts), dtype=hc.dtype, fill_value=hc.fill_value)
hci.mask = np.zeros((npts), dtype=bool)
#-- interpolate amplitude and phase of the constituent
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
hc[hc.mask] = np.nan
#-- use quick bilinear to interpolate values
hci.data[:] = bilinear_interp(lon,
lat,
hc,
ilon,
ilat,
dtype=hc.dtype)
#-- replace nan values with fill_value
hci.mask[:] |= np.isnan(hci.data)
hci.data[hci.mask] = hci.fill_value
elif (METHOD == 'spline'):
#-- interpolate complex form of the constituent with scipy
f1 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.data.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.data.imag.T,
kx=1,
ky=1)
f3 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.mask.T,
kx=1,
ky=1)
hci.data.real[:] = f1.ev(ilon, ilat)
hci.data.imag[:] = f2.ev(ilon, ilat)
hci.mask[:] = f3.ev(ilon, ilat).astype(bool)
#-- replace invalid values with fill_value
hci.data[hci.mask] = hci.fill_value
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator(
(lat, lon),
hc.data,
method=METHOD,
bounds_error=False,
fill_value=hci.fill_value)
r2 = scipy.interpolate.RegularGridInterpolator((lat, lon),
hc.mask,
method=METHOD,
bounds_error=False,
fill_value=1)
hci.data[:] = r1.__call__(np.c_[ilat, ilon])
hci.mask[:] = np.ceil(r2.__call__(np.c_[ilat, ilon])).astype(bool)
#-- replace invalid values with fill_value
hci.mask[:] |= (hci.data == hci.fill_value)
hci.data[hci.mask] = hci.fill_value
#-- extrapolate data using nearest-neighbors
if EXTRAPOLATE and np.any(hci.mask):
#-- find invalid data points
inv, = np.nonzero(hci.mask)
#-- replace invalid values with nan
hc[hc.mask] = np.nan
#-- extrapolate points within 10km of valid model points
hci.data[inv] = nearest_extrap(lon,
lat,
hc,
ilon[inv],
ilat[inv],
dtype=hc.dtype,
cutoff=10.0)
#-- replace nan values with fill_value
hci.mask[inv] = np.isnan(hci.data[inv])
hci.data[hci.mask] = hci.fill_value
#-- convert amplitude from input units to meters
amplitude.data[:, i] = np.abs(hci.data) * SCALE
amplitude.mask[:, i] = np.copy(hci.mask)
#-- phase of the constituent in radians
ph.data[:, i] = np.arctan2(-np.imag(hci.data), np.real(hci.data))
ph.mask[:, i] = np.copy(hci.mask)
#-- convert phase to degrees
phase = ph * 180.0 / np.pi
phase.data[phase.data < 0] += 360.0
#-- replace data for invalid mask values
amplitude.data[amplitude.mask] = amplitude.fill_value
phase.data[phase.mask] = phase.fill_value
#-- return the interpolated values
return (amplitude, phase, constituents)
def check_tide_points(x,y,DIRECTORY=None,MODEL=None,EPSG=3031,METHOD='spline'):
"""
Check if points are within a tide model domain
Arguments
---------
x: x-coordinates in projection EPSG
y: y-coordinates in projection EPSG
Keyword arguments
-----------------
DIRECTORY: working data directory for tide models
MODEL: Tide model to use in correction
EPSG: input coordinate system
default: 3031 Polar Stereographic South, WGS84
METHOD: interpolation method
bilinear: quick bilinear interpolation
spline: scipy bivariate spline interpolation
linear, nearest: scipy regular grid interpolations
Returns
-------
valid: array describing if input coordinate is within model domain
"""
# select between tide models
if (MODEL == 'CATS0201'):
grid_file = os.path.join(DIRECTORY,'cats0201_tmd','grid_CATS')
model_format = 'OTIS'
model_EPSG = '4326'
elif (MODEL == 'CATS2008'):
grid_file = os.path.join(DIRECTORY,'CATS2008','grid_CATS2008')
model_format = 'OTIS'
model_EPSG = 'CATS2008'
elif (MODEL == 'TPXO9-atlas'):
grid_file = os.path.join(DIRECTORY,'TPXO9_atlas','grid_tpxo9_atlas.nc.gz')
model_format = 'netcdf'
elif (MODEL == 'TPXO9-atlas-v2'):
grid_file = os.path.join(DIRECTORY,'TPXO9_atlas_v2','grid_tpxo9_atlas_30_v2.nc.gz')
model_format = 'netcdf'
elif (MODEL == 'TPXO9-atlas-v3'):
grid_file = os.path.join(DIRECTORY,'TPXO9_atlas_v3','grid_tpxo9_atlas_30_v3.nc.gz')
model_format = 'netcdf'
elif (MODEL == 'TPXO9-atlas-v4'):
grid_file = os.path.join(DIRECTORY,'TPXO9_atlas_v4','grid_tpxo9_atlas_30_v4')
model_format = 'OTIS'
model_EPSG = '4326'
elif (MODEL == 'TPXO9.1'):
grid_file = os.path.join(DIRECTORY,'TPXO9.1','DATA','grid_tpxo9')
model_format = 'OTIS'
model_EPSG = '4326'
elif (MODEL == 'TPXO8-atlas'):
grid_file = os.path.join(DIRECTORY,'tpxo8_atlas','grid_tpxo8atlas_30_v1')
model_format = 'ATLAS'
model_EPSG = '4326'
elif (MODEL == 'TPXO7.2'):
grid_file = os.path.join(DIRECTORY,'TPXO7.2_tmd','grid_tpxo7.2')
model_format = 'OTIS'
model_EPSG = '4326'
elif (MODEL == 'AODTM-5'):
grid_file = os.path.join(DIRECTORY,'aodtm5_tmd','grid_Arc5km')
model_format = 'OTIS'
model_EPSG = 'PSNorth'
elif (MODEL == 'AOTIM-5'):
grid_file = os.path.join(DIRECTORY,'aotim5_tmd','grid_Arc5km')
model_format = 'OTIS'
model_EPSG = 'PSNorth'
elif (MODEL == 'AOTIM-5-2018'):
grid_file = os.path.join(DIRECTORY,'Arc5km2018','grid_Arc5km2018')
model_format = 'OTIS'
model_EPSG = 'PSNorth'
elif (MODEL == 'GOT4.7'):
model_directory = os.path.join(DIRECTORY,'GOT4.7','grids_oceantide')
model_files = ['q1.d.gz','o1.d.gz','p1.d.gz','k1.d.gz','n2.d.gz',
'm2.d.gz','s2.d.gz','k2.d.gz','s1.d.gz','m4.d.gz']
model_format = 'GOT'
elif (MODEL == 'GOT4.8'):
model_directory = os.path.join(DIRECTORY,'got4.8','grids_oceantide')
model_files = ['q1.d.gz','o1.d.gz','p1.d.gz','k1.d.gz','n2.d.gz',
'm2.d.gz','s2.d.gz','k2.d.gz','s1.d.gz','m4.d.gz']
model_format = 'GOT'
elif (MODEL == 'GOT4.10'):
model_directory = os.path.join(DIRECTORY,'GOT4.10c','grids_oceantide')
model_files = ['q1.d.gz','o1.d.gz','p1.d.gz','k1.d.gz','n2.d.gz',
'm2.d.gz','s2.d.gz','k2.d.gz','s1.d.gz','m4.d.gz']
model_format = 'GOT'
elif (MODEL == 'FES2014'):
model_directory = os.path.join(DIRECTORY,'fes2014','ocean_tide')
model_files = ['2n2.nc.gz','eps2.nc.gz','j1.nc.gz','k1.nc.gz',
'k2.nc.gz','l2.nc.gz','la2.nc.gz','m2.nc.gz','m3.nc.gz','m4.nc.gz',
'm6.nc.gz','m8.nc.gz','mf.nc.gz','mks2.nc.gz','mm.nc.gz',
'mn4.nc.gz','ms4.nc.gz','msf.nc.gz','msqm.nc.gz','mtm.nc.gz',
'mu2.nc.gz','n2.nc.gz','n4.nc.gz','nu2.nc.gz','o1.nc.gz','p1.nc.gz',
'q1.nc.gz','r2.nc.gz','s1.nc.gz','s2.nc.gz','s4.nc.gz','sa.nc.gz',
'ssa.nc.gz','t2.nc.gz']
model_format = 'FES'
# input shape of data
idim = np.shape(x)
# converting x,y from EPSG to latitude/longitude
try:
# EPSG projection code string or int
crs1 = pyproj.CRS.from_string("epsg:{0:d}".format(int(EPSG)))
except (ValueError,pyproj.exceptions.CRSError):
# Projection SRS string
crs1 = pyproj.CRS.from_string(EPSG)
crs2 = pyproj.CRS.from_string("epsg:{0:d}".format(4326))
transformer = pyproj.Transformer.from_crs(crs1, crs2, always_xy=True)
lon,lat = transformer.transform(np.atleast_1d(x).flatten(),
np.atleast_1d(y).flatten())
# read tidal constants and interpolate to grid points
if model_format in ('OTIS','ATLAS'):
# if reading a single OTIS solution
xi,yi,hz,mz,iob,dt = pyTMD.read_tide_model.read_tide_grid(grid_file)
# invert model mask
mz = np.logical_not(mz)
# adjust dimensions of input coordinates to be iterable
# run wrapper function to convert coordinate systems of input lat/lon
X,Y = pyTMD.convert_ll_xy(lon,lat,model_EPSG,'F')
elif (model_format == 'netcdf'):
# if reading a netCDF OTIS atlas solution
xi,yi,hz = pyTMD.read_netcdf_model.read_netcdf_grid(grid_file,
GZIP=True, TYPE='z')
# copy bathymetry mask
mz = np.copy(hz.mask)
# copy latitude and longitude and adjust longitudes
X,Y = np.copy([lon,lat]).astype(np.float64)
lt0, = np.nonzero(X < 0)
X[lt0] += 360.0
elif (model_format == 'GOT'):
# if reading a NASA GOT solution
input_file = os.path.join(model_directory,model_files[0])
hc,xi,yi,c = pyTMD.read_GOT_model.read_GOT_grid(input_file, GZIP=True)
# copy tidal constituent mask
mz = np.copy(hc.mask)
# copy latitude and longitude and adjust longitudes
X,Y = np.copy([lon,lat]).astype(np.float64)
lt0, = np.nonzero(X < 0)
X[lt0] += 360.0
elif (model_format == 'FES'):
# if reading a FES netCDF solution
input_file = os.path.join(model_directory,model_files[0])
hc,xi,yi = pyTMD.read_FES_model.read_netcdf_file(input_file,GZIP=True,
TYPE='z',VERSION='FES2014')
# copy tidal constituent mask
mz = np.copy(hc.mask)
# copy latitude and longitude and adjust longitudes
X,Y = np.copy([lon,lat]).astype(np.float64)
lt0, = np.nonzero(X < 0)
X[lt0] += 360.0
# interpolate masks
if (METHOD == 'bilinear'):
# replace invalid values with nan
mz1 = bilinear_interp(xi,yi,mz,X,Y)
mask = np.floor(mz1).astype(mz.dtype)
elif (METHOD == 'spline'):
f1=scipy.interpolate.RectBivariateSpline(xi,yi,mz.T,kx=1,ky=1)
mask = np.floor(f1.ev(X,Y)).astype(mz.dtype)
else:
# use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator((yi,xi),mz,
method=METHOD,bounds_error=False,fill_value=1)
mask = np.floor(r1.__call__(np.c_[y,x])).astype(mz.dtype)
# reshape to original dimensions
valid = np.logical_not(mask).reshape(idim).astype(mz.dtype)
# replace points outside model domain with invalid
valid &= (X >= xi.min()) & (X <= xi.max())
valid &= (Y >= yi.min()) & (Y <= yi.max())
# return the valid mask
return valid
def extract_FES_constants(ilon,
ilat,
directory,
model_files,
TYPE='z',
VERSION=None,
METHOD='spline',
GZIP=True,
SCALE=1):
"""
Reads files for an ascii or netCDF4 tidal model
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Arguments
---------
ilon: longitude to interpolate
ilat: latitude to interpolate
directory: data directory for tide data files
grid_file: grid file for model (can be gzipped)
model_files: list of model files for each constituent (can be gzipped)
Keyword arguments
-----------------
TYPE: tidal variable to run
z: heights
u: horizontal transport velocities
v: vertical transport velocities
VERSION: model version to run
FES1999
FES2004
FES2012
FES2014
METHOD: interpolation method
bilinear: quick bilinear interpolation
spline: scipy bivariate spline interpolation
linear, nearest: scipy regular grid interpolations
GZIP: input files are compressed
SCALE: scaling factor for converting to output units
Returns
-------
amplitude: amplitudes of tidal constituents
phase: phases of tidal constituents
"""
#-- adjust dimensions of input coordinates to be iterable
ilon = np.atleast_1d(ilon)
ilat = np.atleast_1d(ilat)
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
if (np.min(ilon) < 0.0):
lt0, = np.nonzero(ilon < 0)
ilon[lt0] += 360.0
#-- number of points
npts = len(ilon)
#-- number of constituents
nc = len(model_files)
#-- amplitude and phase
amplitude = np.ma.zeros((npts, nc))
amplitude.mask = np.zeros((npts, nc), dtype=np.bool)
phase = np.ma.zeros((npts, nc))
phase.mask = np.zeros((npts, nc), dtype=np.bool)
#-- read and interpolate each constituent
for i, fi in enumerate(model_files):
#-- read constituent from elevation file
if VERSION in ('FES1999', 'FES2004'):
hc, lon, lat = read_ascii_file(os.path.join(directory, fi),
GZIP=GZIP,
TYPE=TYPE,
VERSION=VERSION)
elif VERSION in ('FES2012', 'FES2014'):
hc, lon, lat = read_netcdf_file(os.path.join(directory, fi),
GZIP=GZIP,
TYPE=TYPE,
VERSION=VERSION)
#-- interpolated complex form of constituent oscillation
hci = np.ma.zeros((npts), dtype=hc.dtype, fill_value=hc.fill_value)
hci.mask = np.zeros((npts), dtype=np.bool)
#-- interpolate amplitude and phase of the constituent
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
hc[hc.mask] = np.nan
#-- use quick bilinear to interpolate values
hci.data[:] = bilinear_interp(lon,
lat,
hc,
ilon,
ilat,
dtype=hc.dtype)
#-- replace nan values with fill_value
hci.mask[:] |= np.isnan(hci.data)
hci.data[hci.mask] = hci.fill_value
elif (METHOD == 'spline'):
#-- interpolate complex form of the constituent with scipy
f1 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.data.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.data.imag.T,
kx=1,
ky=1)
f3 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.mask.T,
kx=1,
ky=1)
hci.data.real[:] = f1.ev(ilon, ilat)
hci.data.imag[:] = f2.ev(ilon, ilat)
hci.mask[:] = f3.ev(ilon, ilat).astype(np.bool)
#-- replace invalid values with fill_value
hci.data[hci.mask] = hci.fill_value
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator(
(lat, lon),
hc.data,
method=METHOD,
bounds_error=False,
fill_value=hci.fill_value)
r2 = scipy.interpolate.RegularGridInterpolator((lat, lon),
hc.mask,
method=METHOD,
bounds_error=False,
fill_value=1)
hci.data[:] = r1.__call__(np.c_[ilat, ilon])
hci.mask[:] = np.ceil(r2.__call__(np.c_[ilat,
ilon])).astype(np.bool)
#-- replace invalid values with fill_value
hci.mask[:] |= (hci.data == hci.fill_value)
hci.data[hci.mask] = hci.fill_value
#-- convert amplitude from input units to meters
amplitude.data[:, i] = np.abs(hci) * SCALE
amplitude.mask[:, i] = np.copy(hci.mask)
#-- convert phase to degrees
phase.data[:,
i] = np.arctan2(-np.imag(hci), np.real(hci)) * 180.0 / np.pi
phase.mask[:, i] = np.copy(hci.mask)
phase.data[phase.data < 0] += 360.0
#-- replace data for invalid mask values
amplitude.data[amplitude.mask] = amplitude.fill_value
phase.data[phase.mask] = phase.fill_value
#-- return the interpolated values
return (amplitude, phase)
def check_tide_points(x, y, DIRECTORY=None, MODEL=None,
ATLAS_FORMAT='netcdf', GZIP=False, DEFINITION_FILE=None,
EPSG=3031, METHOD='spline'):
"""
Check if points are within a tide model domain
Parameters
----------
x: float
x-coordinates in projection EPSG
y: float
y-coordinates in projection EPSG
DIRECTORY: str or NoneType, default None
working data directory for tide models
MODEL: str or NoneType, default None
Tide model to use
ATLAS_FORMAT: str, default 'netcdf'
ATLAS tide model format
- ``'OTIS'``
- ``'netcdf'``
GZIP: bool, default False
Tide model files are gzip compressed
DEFINITION_FILE: str or NoneType, default None
Tide model definition file for use
EPSG: int, default: 3031 (Polar Stereographic South, WGS84)
Input coordinate system
METHOD: str
interpolation method
- ```bilinear```: quick bilinear interpolation
- ```spline```: scipy bivariate spline interpolation
- ```linear```, ```nearest```: scipy regular grid interpolations
Returns
-------
valid: bool
array describing if input coordinate is within model domain
"""
#-- check that tide directory is accessible
try:
os.access(DIRECTORY, os.F_OK)
except:
raise FileNotFoundError("Invalid tide directory")
#-- get parameters for tide model
if DEFINITION_FILE is not None:
model = pyTMD.model(DIRECTORY).from_file(DEFINITION_FILE)
else:
model = pyTMD.model(DIRECTORY, format=ATLAS_FORMAT,
compressed=GZIP).elevation(MODEL)
# input shape of data
idim = np.shape(x)
# converting x,y from EPSG to latitude/longitude
try:
# EPSG projection code string or int
crs1 = pyproj.CRS.from_string("epsg:{0:d}".format(int(EPSG)))
except (ValueError,pyproj.exceptions.CRSError):
# Projection SRS string
crs1 = pyproj.CRS.from_string(EPSG)
crs2 = pyproj.CRS.from_string("epsg:{0:d}".format(4326))
transformer = pyproj.Transformer.from_crs(crs1, crs2, always_xy=True)
lon,lat = transformer.transform(np.atleast_1d(x).flatten(),
np.atleast_1d(y).flatten())
# read tidal constants and interpolate to grid points
if model.format in ('OTIS','ATLAS'):
# if reading a single OTIS solution
xi,yi,hz,mz,iob,dt = pyTMD.read_tide_model.read_tide_grid(model.grid_file)
# invert model mask
mz = np.logical_not(mz)
# adjust dimensions of input coordinates to be iterable
# run wrapper function to convert coordinate systems of input lat/lon
X,Y = pyTMD.convert_ll_xy(lon,lat,model.projection,'F')
elif (model.format == 'netcdf'):
# if reading a netCDF OTIS atlas solution
xi,yi,hz = pyTMD.read_netcdf_model.read_netcdf_grid(model.grid_file,
GZIP=model.compressed, TYPE=model.type)
# copy bathymetry mask
mz = np.copy(hz.mask)
# copy latitude and longitude and adjust longitudes
X,Y = np.copy([lon,lat]).astype(np.float64)
lt0, = np.nonzero(X < 0)
X[lt0] += 360.0
elif (model.format == 'GOT'):
# if reading a NASA GOT solution
hc,xi,yi,c = pyTMD.read_GOT_model.read_GOT_grid(model.model_file[0],
GZIP=model.compressed)
# copy tidal constituent mask
mz = np.copy(hc.mask)
# copy latitude and longitude and adjust longitudes
X,Y = np.copy([lon,lat]).astype(np.float64)
lt0, = np.nonzero(X < 0)
X[lt0] += 360.0
elif (model.format == 'FES'):
# if reading a FES netCDF solution
hc,xi,yi = pyTMD.read_FES_model.read_netcdf_file(model.model_file[0],
GZIP=model.compressed, TYPE=model.type, VERSION=model.version)
# copy tidal constituent mask
mz = np.copy(hc.mask)
# copy latitude and longitude and adjust longitudes
X,Y = np.copy([lon,lat]).astype(np.float64)
lt0, = np.nonzero(X < 0)
X[lt0] += 360.0
# interpolate masks
if (METHOD == 'bilinear'):
# replace invalid values with nan
mz1 = bilinear_interp(xi,yi,mz,X,Y)
mask = np.floor(mz1).astype(mz.dtype)
elif (METHOD == 'spline'):
f1=scipy.interpolate.RectBivariateSpline(xi,yi,mz.T,kx=1,ky=1)
mask = np.floor(f1.ev(X,Y)).astype(mz.dtype)
else:
# use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator((yi,xi),mz,
method=METHOD,bounds_error=False,fill_value=1)
mask = np.floor(r1.__call__(np.c_[y,x])).astype(mz.dtype)
# reshape to original dimensions
valid = np.logical_not(mask).reshape(idim).astype(mz.dtype)
# replace points outside model domain with invalid
valid &= (X >= xi.min()) & (X <= xi.max())
valid &= (Y >= yi.min()) & (Y <= yi.max())
# return the valid mask
return valid
def extract_FES_constants(ilon, ilat, model_files, TYPE='z', VERSION=None,
METHOD='spline', EXTRAPOLATE=False, CUTOFF=10.0, GZIP=True, SCALE=1.0):
"""
Reads files for an ascii or netCDF4 tidal model
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Parameters
----------
ilon: float
longitude to interpolate
ilat: float
latitude to interpolate
grid_file: str
grid file for model
model_files: list
list of model files for each constituent
TYPE: str, default 'z'
Tidal variable to read
- ``'z'``: heights
- ``'u'``: horizontal transport velocities
- ``'v'``: vertical transport velocities
VERSION: str or NoneType, default None
Model version to read
- ``'FES1999'``
- ``'FES2004'``
- ``'FES2012'``
- ``'FES2014'``
- ``'EOT20'``
METHOD: str, default 'spline'
Interpolation method
- ``'bilinear'``: quick bilinear interpolation
- ``'spline'``: scipy bivariate spline interpolation
- ``'linear'``, ``'nearest'``: scipy regular grid interpolations
EXTRAPOLATE: bool, default False
Extrapolate model using nearest-neighbors
CUTOFF: float, default 10.0
Extrapolation cutoff in kilometers
Set to np.inf to extrapolate for all points
GZIP: bool, default False
Input files are compressed
SCALE: float, default 1.0
Scaling factor for converting to output units
Returns
-------
amplitude: float
amplitudes of tidal constituents
phase: float
phases of tidal constituents
"""
#-- raise warning if model files are entered as a string
if isinstance(model_files,str):
warnings.warn("Tide model is entered as a string")
model_files = [model_files]
#-- adjust dimensions of input coordinates to be iterable
ilon = np.atleast_1d(ilon)
ilat = np.atleast_1d(ilat)
#-- number of points
npts = len(ilon)
#-- number of constituents
nc = len(model_files)
#-- amplitude and phase
amplitude = np.ma.zeros((npts,nc))
amplitude.mask = np.zeros((npts,nc),dtype=bool)
ph = np.ma.zeros((npts,nc))
ph.mask = np.zeros((npts,nc),dtype=bool)
#-- read and interpolate each constituent
for i,fi in enumerate(model_files):
#-- check that model file is accessible
if not os.access(os.path.expanduser(fi), os.F_OK):
raise FileNotFoundError(os.path.expanduser(fi))
#-- read constituent from elevation file
if VERSION in ('FES1999','FES2004'):
#-- FES ascii constituent files
hc,lon,lat = read_ascii_file(os.path.expanduser(fi),
GZIP=GZIP, TYPE=TYPE, VERSION=VERSION)
elif VERSION in ('FES2012','FES2014','EOT20'):
#-- FES netCDF4 constituent files
hc,lon,lat = read_netcdf_file(os.path.expanduser(fi),
GZIP=GZIP, TYPE=TYPE, VERSION=VERSION)
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
if (np.min(ilon) < 0.0) & (np.max(lon) > 180.0):
#-- input points convention (-180:180)
#-- tide model convention (0:360)
ilon[ilon<0.0] += 360.0
elif (np.max(ilon) > 180.0) & (np.min(lon) < 0.0):
#-- input points convention (0:360)
#-- tide model convention (-180:180)
ilon[ilon>180.0] -= 360.0
#-- interpolated complex form of constituent oscillation
hci = np.ma.zeros((npts),dtype=hc.dtype,fill_value=hc.fill_value)
hci.mask = np.zeros((npts),dtype=bool)
#-- interpolate amplitude and phase of the constituent
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
hc[hc.mask] = np.nan
#-- use quick bilinear to interpolate values
hci.data[:] = bilinear_interp(lon,lat,hc,ilon,ilat,dtype=hc.dtype)
#-- replace nan values with fill_value
hci.mask[:] |= np.isnan(hci.data)
hci.data[hci.mask] = hci.fill_value
elif (METHOD == 'spline'):
#-- interpolate complex form of the constituent with scipy
f1=scipy.interpolate.RectBivariateSpline(lon,lat,
hc.data.real.T,kx=1,ky=1)
f2=scipy.interpolate.RectBivariateSpline(lon,lat,
hc.data.imag.T,kx=1,ky=1)
f3=scipy.interpolate.RectBivariateSpline(lon,lat,
hc.mask.T,kx=1,ky=1)
hci.data.real[:] = f1.ev(ilon,ilat)
hci.data.imag[:] = f2.ev(ilon,ilat)
hci.mask[:] = f3.ev(ilon,ilat).astype(bool)
#-- replace invalid values with fill_value
hci.data[hci.mask] = hci.fill_value
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator((lat,lon),
hc.data, method=METHOD, bounds_error=False,
fill_value=hci.fill_value)
r2 = scipy.interpolate.RegularGridInterpolator((lat,lon),
hc.mask, method=METHOD, bounds_error=False, fill_value=1)
hci.data[:] = r1.__call__(np.c_[ilat,ilon])
hci.mask[:] = np.ceil(r2.__call__(np.c_[ilat,ilon])).astype(bool)
#-- replace invalid values with fill_value
hci.mask[:] |= (hci.data == hci.fill_value)
hci.data[hci.mask] = hci.fill_value
#-- extrapolate data using nearest-neighbors
if EXTRAPOLATE and np.any(hci.mask):
#-- find invalid data points
inv, = np.nonzero(hci.mask)
#-- replace invalid values with nan
hc[hc.mask] = np.nan
#-- extrapolate points within cutoff of valid model points
hci[inv] = nearest_extrap(lon,lat,hc,ilon[inv],ilat[inv],
dtype=hc.dtype,cutoff=CUTOFF)
#-- convert amplitude from input units to meters
amplitude.data[:,i] = np.abs(hci.data)*SCALE
amplitude.mask[:,i] = np.copy(hci.mask)
#-- phase of the constituent in radians
ph.data[:,i] = np.arctan2(-np.imag(hci.data),np.real(hci.data))
ph.mask[:,i] = np.copy(hci.mask)
#-- convert phase to degrees
phase = ph*180.0/np.pi
phase.data[phase.data < 0] += 360.0
#-- replace data for invalid mask values
amplitude.data[amplitude.mask] = amplitude.fill_value
phase.data[phase.mask] = phase.fill_value
#-- return the interpolated values
return (amplitude,phase)
def extract_netcdf_constants(ilon, ilat, directory, grid_file, model_files,
TYPE='z', METHOD='spline', GZIP=True, SCALE=1):
"""
Reads files for a netCDF4 tidal model
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Arguments
---------
ilon: longitude to interpolate
ilat: latitude to interpolate
directory: data directory for tide data files
grid_file: grid file for model (can be gzipped)
model_files: list of model files for each constituent (can be gzipped)
TYPE: tidal variable to run
z: heights
u: horizontal transport velocities
U: horizontal depth-averaged transport
v: vertical transport velocities
V: vertical depth-averaged transport
Keyword arguments
-----------------
METHOD: interpolation method
bilinear: quick bilinear interpolation
spline: scipy bivariate spline interpolation
linear, nearest: scipy regular grid interpolations
GZIP: input netCDF4 files are compressed
SCALE: scaling factor for converting to output units
Returns
-------
amplitude: amplitudes of tidal constituents
phase: phases of tidal constituents
D: bathymetry of tide model
constituents: list of model constituents
"""
#-- read the netcdf format tide grid file
#-- reading a combined global solution with localized solutions
if GZIP:
#-- open remote file with netCDF4
#-- read GZIP file
f = gzip.open(os.path.join(directory,grid_file),'rb')
fileID = netCDF4.Dataset(grid_file,'r',memory=f.read())
else:
fileID = netCDF4.Dataset(os.path.join(directory,grid_file),'r')
#-- variable dimensions
nx = fileID.dimensions['nx'].size
ny = fileID.dimensions['ny'].size
#-- allocate numpy masked array for bathymetry
bathymetry = np.ma.zeros((ny,nx))
#-- read bathmetry and coordinates for variable type
if (TYPE == 'z'):
#-- get bathymetry at nodes
bathymetry.data[:,:] = fileID.variables['hz'][:,:].T
#-- read latitude and longitude at z-nodes
lon = fileID.variables['lon_z'][:].copy()
lat = fileID.variables['lat_z'][:].copy()
elif TYPE in ('U','u'):
#-- get bathymetry at u-nodes
bathymetry.data[:,:] = fileID.variables['hu'][:,:].T
#-- read latitude and longitude at u-nodes
lon = fileID.variables['lon_u'][:].copy()
lat = fileID.variables['lat_u'][:].copy()
elif TYPE in ('V','v'):
#-- get bathymetry at v-nodes
bathymetry.data[:,:] = fileID.variables['hv'][:,:].T
#-- read latitude and longitude at v-nodes
lon = fileID.variables['lon_v'][:].copy()
lat = fileID.variables['lat_v'][:].copy()
#-- close the grid file
fileID.close()
f.close() if GZIP else None
#-- grid step size of tide model
dlon = lon[1] - lon[0]
dlat = lat[1] - lat[0]
#-- replace original values with extend arrays/matrices
lon = extend_array(lon, dlon)
bathymetry = extend_matrix(bathymetry)
#-- create masks
bathymetry.mask = (bathymetry.data == 0)
#-- create meshes from latitude and longitude
gridlon,gridlat = np.meshgrid(lon,lat)
#-- adjust dimensions of input coordinates to be iterable
ilon = np.atleast_1d(ilon)
ilat = np.atleast_1d(ilat)
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
lt0, = np.nonzero(ilon < 0)
ilon[lt0] += 360.0
#-- number of points
npts = len(ilon)
#-- interpolate bathymetry and mask to output points
D = np.ma.zeros((npts))
D.mask = np.zeros((npts),dtype=np.bool)
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
bathymetry[bathymetry.mask] = np.nan
#-- use quick bilinear to interpolate values
D.data[:] = bilinear_interp(lon,lat,bathymetry,ilon,ilat)
#-- replace nan values with fill_value
D.mask[:] = np.isnan(D.data)
D.data[D.mask] = D.fill_value
elif (METHOD == 'spline'):
#-- use scipy bivariate splines to interpolate values
f1 = scipy.interpolate.RectBivariateSpline(lon,lat,
bathymetry.data.T,kx=1,ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,lat,
bathymetry.mask.T,kx=1,ky=1)
D.data[:] = f1.ev(ilon,ilat)
D.mask[:] = np.ceil(f2.ev(ilon,ilat).astype(np.bool))
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator((lat,lon),
bathymetry.data, method=METHOD, bounds_error=False)
r2 = scipy.interpolate.RegularGridInterpolator((lat,lon),
bathymetry.mask, method=METHOD, bounds_error=False, fill_value=1)
D.data[:] = r1.__call__(np.c_[ilat,ilon])
D.mask[:] = np.ceil(r2.__call__(np.c_[ilat,ilon])).astype(np.bool)
#-- u and v are velocities in cm/s
if TYPE in ('v','u'):
unit_conv = (D.data/100.0)
#-- U and V are transports in m^2/s
elif TYPE in ('V','U'):
unit_conv = 1.0
#-- number of constituents
nc = len(model_files)
#-- list of constituents
constituents = []
#-- amplitude and phase
ampl = np.ma.zeros((npts,nc))
ampl.mask = np.zeros((npts,nc),dtype=np.bool)
phase = np.ma.zeros((npts,nc))
phase.mask = np.zeros((npts,nc),dtype=np.bool)
#-- read and interpolate each constituent
for i,fi in enumerate(model_files):
if (TYPE == 'z'):
#-- read constituent from elevation file
z,con = read_elevation_file(os.path.join(directory,fi),GZIP)
#-- append constituent to list
constituents.append(con)
#-- replace original values with extend matrices
z = extend_matrix(z)
#-- interpolate amplitude and phase of the constituent
z1 = np.ma.zeros((npts),dtype=z.dtype)
z1.mask = np.zeros((npts),dtype=np.bool)
if (METHOD == 'bilinear'):
z1.data[:] = bilinear_interp(lon,lat,z,ilon,ilat,dtype=z.dtype)
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(lon,lat,
z.data.real.T,kx=1,ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,lat,
z.data.imag.T,kx=1,ky=1)
z1.data.real = f1.ev(ilon,ilat)
z1.data.imag = f2.ev(ilon,ilat)
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator((lat,lon),
z.data, method=METHOD, bounds_error=False,
fill_value=z1.fill_value)
z1.data[:] = r1.__call__(np.c_[ilat,ilon])
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
#-- amplitude and phase of the constituent
ampl[:,i] = np.abs(z1)
phase[:,i] = np.arctan2(-np.imag(z1),np.real(z1))
elif TYPE in ('U','u','V','v'):
#-- read constituent from transport file
tr,con = read_transport_file(os.path.join(directory,fi),TYPE,GZIP)
#-- append constituent to list
constituents.append(con)
#-- replace original values with extend matrices
tr = extend_matrix(tr)
#-- interpolate amplitude and phase of the constituent
tr1 = np.ma.zeros((npts),dtype=tr.dtype)
tr1.mask = np.zeros((npts),dtype=np.bool)
if (METHOD == 'bilinear'):
tr1.data[:]=bilinear_interp(lon,lat,tr,ilon,ilat,dtype=tr.dtype)
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = tr1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(lon,lat,
tr.data.real.T,kx=1,ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,lat,
tr.data.imag.T,kx=1,ky=1)
tr1.data.real = f1.ev(ilon,ilat)
tr1.data.imag = f2.ev(ilon,ilat)
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = z1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator((lat,lon),
tr.data, method=METHOD, bounds_error=False,
fill_value=tr1.fill_value)
tr1.data[:] = r1.__call__(np.c_[ilat,ilon])
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = tr1.fill_value
#-- convert units
tr1 = tr1/unit_conv
#-- amplitude and phase of the constituent
ampl[:,i] = np.abs(tr1)
phase[:,i] = np.arctan2(-np.imag(tr1),np.real(tr1))
#-- convert amplitude from input units to meters
amplitude = ampl*SCALE
#-- convert phase to degrees
phase = phase*180.0/np.pi
phase[phase < 0] += 360.0
#-- return the interpolated values
return (amplitude,phase,D,constituents)
def extract_netcdf_constants(ilon, ilat, grid_file, model_files, TYPE='z',
METHOD='spline', EXTRAPOLATE=False, CUTOFF=10.0, GZIP=True, SCALE=1.0):
"""
Reads files for ATLAS netCDF4 tidal models
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Parameters
----------
ilon: float
longitude to interpolate
ilat: float
latitude to interpolate
grid_file: str
grid file for model
model_files: list
list of model files for each constituent
TYPE: str, default 'z'
Tidal variable to read
- ``'z'``: heights
- ``'u'``: horizontal transport velocities
- ``'U'``: horizontal depth-averaged transport
- ``'v'``: vertical transport velocities
- ``'V'``: vertical depth-averaged transport
METHOD: str, default 'spline'
Interpolation method
- ``'bilinear'``: quick bilinear interpolation
- ``'spline'``: scipy bivariate spline interpolation
- ``'linear'``, ``'nearest'``: scipy regular grid interpolations
EXTRAPOLATE: bool, default False
Extrapolate model using nearest-neighbors
CUTOFF: float, default 10.0
Extrapolation cutoff in kilometers
Set to np.inf to extrapolate for all points
GZIP: bool, default False
Input files are compressed
SCALE: float, default 1.0
Scaling factor for converting to output units
Returns
-------
amplitude: float
amplitudes of tidal constituents
phase: float
phases of tidal constituents
D: float
bathymetry of tide model
constituents: list
list of model constituents
"""
#-- raise warning if model files are entered as a string
if isinstance(model_files,str):
warnings.warn("Tide model is entered as a string")
model_files = [model_files]
#-- check that grid file is accessible
if not os.access(os.path.expanduser(grid_file), os.F_OK):
raise FileNotFoundError(os.path.expanduser(grid_file))
#-- read the tide grid file for bathymetry and spatial coordinates
lon,lat,bathymetry = read_netcdf_grid(grid_file, TYPE, GZIP=GZIP)
#-- adjust dimensions of input coordinates to be iterable
ilon = np.atleast_1d(ilon)
ilat = np.atleast_1d(ilat)
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
if (np.min(ilon) < 0.0) & (np.max(lon) > 180.0):
#-- input points convention (-180:180)
#-- tide model convention (0:360)
ilon[ilon<0.0] += 360.0
elif (np.max(ilon) > 180.0) & (np.min(lon) < 0.0):
#-- input points convention (0:360)
#-- tide model convention (-180:180)
ilon[ilon>180.0] -= 360.0
#-- grid step size of tide model
dlon = lon[1] - lon[0]
dlat = lat[1] - lat[0]
#-- replace original values with extend arrays/matrices
lon = extend_array(lon, dlon)
bathymetry = extend_matrix(bathymetry)
#-- create masks
bathymetry.mask = (bathymetry.data == 0)
#-- number of points
npts = len(ilon)
#-- interpolate bathymetry and mask to output points
D = np.ma.zeros((npts))
D.mask = np.zeros((npts),dtype=bool)
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
bathymetry[bathymetry.mask] = np.nan
#-- use quick bilinear to interpolate values
D.data[:] = bilinear_interp(lon,lat,bathymetry,ilon,ilat)
#-- replace nan values with fill_value
D.mask[:] = np.isnan(D.data)
D.data[D.mask] = D.fill_value
elif (METHOD == 'spline'):
#-- use scipy bivariate splines to interpolate values
f1 = scipy.interpolate.RectBivariateSpline(lon,lat,
bathymetry.data.T,kx=1,ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,lat,
bathymetry.mask.T,kx=1,ky=1)
D.data[:] = f1.ev(ilon,ilat)
D.mask[:] = np.ceil(f2.ev(ilon,ilat).astype(bool))
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator((lat,lon),
bathymetry.data, method=METHOD, bounds_error=False)
r2 = scipy.interpolate.RegularGridInterpolator((lat,lon),
bathymetry.mask, method=METHOD, bounds_error=False, fill_value=1)
D.data[:] = r1.__call__(np.c_[ilat,ilon])
D.mask[:] = np.ceil(r2.__call__(np.c_[ilat,ilon])).astype(bool)
#-- u and v are velocities in cm/s
if TYPE in ('v','u'):
unit_conv = (D.data/100.0)
#-- U and V are transports in m^2/s
elif TYPE in ('V','U'):
unit_conv = 1.0
#-- number of constituents
nc = len(model_files)
#-- list of constituents
constituents = []
#-- amplitude and phase
ampl = np.ma.zeros((npts,nc))
ampl.mask = np.zeros((npts,nc),dtype=bool)
ph = np.ma.zeros((npts,nc))
ph.mask = np.zeros((npts,nc),dtype=bool)
#-- read and interpolate each constituent
for i,model_file in enumerate(model_files):
#-- check that model file is accessible
if not os.access(os.path.expanduser(model_file), os.F_OK):
raise FileNotFoundError(os.path.expanduser(model_file))
if (TYPE == 'z'):
#-- read constituent from elevation file
z,con = read_elevation_file(model_file, GZIP=GZIP)
#-- append constituent to list
constituents.append(con)
#-- replace original values with extend matrices
z = extend_matrix(z)
#-- update constituent mask with bathymetry mask
z.mask[:] |= bathymetry.mask[:]
#-- interpolate amplitude and phase of the constituent
z1 = np.ma.zeros((npts),dtype=z.dtype)
z1.mask = np.zeros((npts),dtype=bool)
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
z[z.mask] = np.nan
z1.data[:] = bilinear_interp(lon,lat,z,ilon,ilat,dtype=z.dtype)
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(lon,lat,
z.data.real.T,kx=1,ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,lat,
z.data.imag.T,kx=1,ky=1)
z1.data.real = f1.ev(ilon,ilat)
z1.data.imag = f2.ev(ilon,ilat)
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator((lat,lon),
z.data, method=METHOD, bounds_error=False,
fill_value=z1.fill_value)
z1.data[:] = r1.__call__(np.c_[ilat,ilon])
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
#-- extrapolate data using nearest-neighbors
if EXTRAPOLATE and np.any(z1.mask):
#-- find invalid data points
inv, = np.nonzero(z1.mask)
#-- replace invalid values with nan
z[z.mask] = np.nan
#-- extrapolate points within cutoff of valid model points
z1[inv] = nearest_extrap(lon,lat,z,ilon[inv],ilat[inv],
dtype=z.dtype,cutoff=CUTOFF)
#-- amplitude and phase of the constituent
ampl.data[:,i] = np.abs(z1.data)
ampl.mask[:,i] = np.copy(z1.mask)
ph.data[:,i] = np.arctan2(-np.imag(z1.data),np.real(z1.data))
ph.mask[:,i] = np.copy(z1.mask)
elif TYPE in ('U','u','V','v'):
#-- read constituent from transport file
tr,con = read_transport_file(model_file, TYPE, GZIP=GZIP)
#-- append constituent to list
constituents.append(con)
#-- replace original values with extend matrices
tr = extend_matrix(tr)
#-- update constituent mask with bathymetry mask
tr.mask[:] |= bathymetry.mask[:]
#-- interpolate amplitude and phase of the constituent
tr1 = np.ma.zeros((npts),dtype=tr.dtype)
tr1.mask = np.zeros((npts),dtype=bool)
if (METHOD == 'bilinear'):
tr1.data[:]=bilinear_interp(lon,lat,tr,ilon,ilat,dtype=tr.dtype)
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = tr1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(lon,lat,
tr.data.real.T,kx=1,ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,lat,
tr.data.imag.T,kx=1,ky=1)
tr1.data.real = f1.ev(ilon,ilat)
tr1.data.imag = f2.ev(ilon,ilat)
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = z1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator((lat,lon),
tr.data, method=METHOD, bounds_error=False,
fill_value=tr1.fill_value)
tr1.data[:] = r1.__call__(np.c_[ilat,ilon])
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = tr1.fill_value
#-- extrapolate data using nearest-neighbors
if EXTRAPOLATE and np.any(tr1.mask):
#-- find invalid data points
inv, = np.nonzero(tr1.mask)
#-- replace invalid values with nan
tr[tr.mask] = np.nan
#-- extrapolate points within cutoff of valid model points
tr1[inv] = nearest_extrap(lon,lat,tr,ilon[inv],ilat[inv],
dtype=tr.dtype,cutoff=CUTOFF)
#-- convert units
#-- amplitude and phase of the constituent
ampl.data[:,i] = np.abs(tr1.data)/unit_conv
ampl.mask[:,i] = np.copy(tr1.mask)
ph.data[:,i] = np.arctan2(-np.imag(tr1.data),np.real(tr1.data))
ph.mask[:,i] = np.copy(tr1.mask)
#-- convert amplitude from input units to meters
amplitude = ampl*SCALE
#-- convert phase to degrees
phase = ph*180.0/np.pi
phase[phase < 0] += 360.0
#-- return the interpolated values
return (amplitude,phase,D,constituents)
def extract_netcdf_constants(ilon,
ilat,
grid_file,
model_files,
TYPE='z',
METHOD='spline',
EXTRAPOLATE=False,
GZIP=True,
SCALE=1.0):
"""
Reads files for a netCDF4 tidal model
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Arguments
---------
ilon: longitude to interpolate
ilat: latitude to interpolate
grid_file: grid file for model (can be gzipped)
model_files: list of model files for each constituent (can be gzipped)
Keyword arguments
-----------------
TYPE: tidal variable to read
z: heights
u: horizontal transport velocities
U: horizontal depth-averaged transport
v: vertical transport velocities
V: vertical depth-averaged transport
METHOD: interpolation method
bilinear: quick bilinear interpolation
spline: scipy bivariate spline interpolation
linear, nearest: scipy regular grid interpolations
EXTRAPOLATE: extrapolate model using nearest-neighbors
GZIP: input netCDF4 files are compressed
SCALE: scaling factor for converting to output units
Returns
-------
amplitude: amplitudes of tidal constituents
phase: phases of tidal constituents
D: bathymetry of tide model
constituents: list of model constituents
"""
#-- read the tide grid file for bathymetry and spatial coordinates
lon, lat, bathymetry = read_netcdf_grid(grid_file, TYPE, GZIP=GZIP)
#-- grid step size of tide model
dlon = lon[1] - lon[0]
dlat = lat[1] - lat[0]
#-- replace original values with extend arrays/matrices
lon = extend_array(lon, dlon)
bathymetry = extend_matrix(bathymetry)
#-- create masks
bathymetry.mask = (bathymetry.data == 0)
#-- adjust dimensions of input coordinates to be iterable
ilon = np.atleast_1d(ilon)
ilat = np.atleast_1d(ilat)
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
lt0, = np.nonzero(ilon < 0)
ilon[lt0] += 360.0
#-- number of points
npts = len(ilon)
#-- interpolate bathymetry and mask to output points
D = np.ma.zeros((npts))
D.mask = np.zeros((npts), dtype=bool)
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
bathymetry[bathymetry.mask] = np.nan
#-- use quick bilinear to interpolate values
D.data[:] = bilinear_interp(lon, lat, bathymetry, ilon, ilat)
#-- replace nan values with fill_value
D.mask[:] = np.isnan(D.data)
D.data[D.mask] = D.fill_value
elif (METHOD == 'spline'):
#-- use scipy bivariate splines to interpolate values
f1 = scipy.interpolate.RectBivariateSpline(lon,
lat,
bathymetry.data.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,
lat,
bathymetry.mask.T,
kx=1,
ky=1)
D.data[:] = f1.ev(ilon, ilat)
D.mask[:] = np.ceil(f2.ev(ilon, ilat).astype(bool))
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator((lat, lon),
bathymetry.data,
method=METHOD,
bounds_error=False)
r2 = scipy.interpolate.RegularGridInterpolator((lat, lon),
bathymetry.mask,
method=METHOD,
bounds_error=False,
fill_value=1)
D.data[:] = r1.__call__(np.c_[ilat, ilon])
D.mask[:] = np.ceil(r2.__call__(np.c_[ilat, ilon])).astype(bool)
#-- u and v are velocities in cm/s
if TYPE in ('v', 'u'):
unit_conv = (D.data / 100.0)
#-- U and V are transports in m^2/s
elif TYPE in ('V', 'U'):
unit_conv = 1.0
#-- number of constituents
nc = len(model_files)
#-- list of constituents
constituents = []
#-- amplitude and phase
ampl = np.ma.zeros((npts, nc))
ampl.mask = np.zeros((npts, nc), dtype=bool)
ph = np.ma.zeros((npts, nc))
ph.mask = np.zeros((npts, nc), dtype=bool)
#-- read and interpolate each constituent
for i, model_file in enumerate(model_files):
if (TYPE == 'z'):
#-- read constituent from elevation file
z, con = read_elevation_file(model_file, GZIP=GZIP)
#-- append constituent to list
constituents.append(con)
#-- replace original values with extend matrices
z = extend_matrix(z)
#-- interpolate amplitude and phase of the constituent
z1 = np.ma.zeros((npts), dtype=z.dtype)
z1.mask = np.zeros((npts), dtype=bool)
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
z[z.mask] = np.nan
z1.data[:] = bilinear_interp(lon,
lat,
z,
ilon,
ilat,
dtype=z.dtype)
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(lon,
lat,
z.data.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,
lat,
z.data.imag.T,
kx=1,
ky=1)
z1.data.real = f1.ev(ilon, ilat)
z1.data.imag = f2.ev(ilon, ilat)
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator(
(lat, lon),
z.data,
method=METHOD,
bounds_error=False,
fill_value=z1.fill_value)
z1.data[:] = r1.__call__(np.c_[ilat, ilon])
#-- mask invalid values
z1.mask[:] |= np.copy(D.mask)
z1.data[z1.mask] = z1.fill_value
#-- extrapolate data using nearest-neighbors
if EXTRAPOLATE and np.any(z1.mask):
#-- find invalid data points
inv, = np.nonzero(z1.mask)
#-- replace invalid values with nan
z[z.mask] = np.nan
#-- extrapolate points within 10km of valid model points
z1.data[inv] = nearest_extrap(lon,
lat,
z,
ilon[inv],
ilat[inv],
dtype=z.dtype,
cutoff=10.0)
#-- replace nan values with fill_value
z1.mask[inv] = np.isnan(z1.data[inv])
z1.data[z1.mask] = z1.fill_value
#-- amplitude and phase of the constituent
ampl.data[:, i] = np.abs(z1.data)
ampl.mask[:, i] = np.copy(z1.mask)
ph.data[:, i] = np.arctan2(-np.imag(z1.data), np.real(z1.data))
ph.mask[:, i] = np.copy(z1.mask)
elif TYPE in ('U', 'u', 'V', 'v'):
#-- read constituent from transport file
tr, con = read_transport_file(model_file, TYPE, GZIP=GZIP)
#-- append constituent to list
constituents.append(con)
#-- replace original values with extend matrices
tr = extend_matrix(tr)
#-- interpolate amplitude and phase of the constituent
tr1 = np.ma.zeros((npts), dtype=tr.dtype)
tr1.mask = np.zeros((npts), dtype=bool)
if (METHOD == 'bilinear'):
tr1.data[:] = bilinear_interp(lon,
lat,
tr,
ilon,
ilat,
dtype=tr.dtype)
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = tr1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(lon,
lat,
tr.data.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,
lat,
tr.data.imag.T,
kx=1,
ky=1)
tr1.data.real = f1.ev(ilon, ilat)
tr1.data.imag = f2.ev(ilon, ilat)
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = z1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator(
(lat, lon),
tr.data,
method=METHOD,
bounds_error=False,
fill_value=tr1.fill_value)
tr1.data[:] = r1.__call__(np.c_[ilat, ilon])
#-- mask invalid values
tr1.mask[:] |= np.copy(D.mask)
tr1.data[tr1.mask] = tr1.fill_value
#-- extrapolate data using nearest-neighbors
if EXTRAPOLATE and np.any(tr1.mask):
#-- find invalid data points
inv, = np.nonzero(tr1.mask)
#-- replace invalid values with nan
tr[tr.mask] = np.nan
#-- extrapolate points within 10km of valid model points
tr1.data[inv] = nearest_extrap(lon,
lat,
tr,
ilon[inv],
ilat[inv],
dtype=tr.dtype,
cutoff=10.0)
#-- replace nan values with fill_value
tr1.mask[inv] = np.isnan(tr1.data[inv])
tr1.data[tr1.mask] = tr1.fill_value
#-- convert units
#-- amplitude and phase of the constituent
ampl.data[:, i] = np.abs(tr1.data) / unit_conv
ampl.mask[:, i] = np.copy(tr1.mask)
ph.data[:, i] = np.arctan2(-np.imag(tr1.data), np.real(tr1.data))
ph.mask[:, i] = np.copy(tr1.mask)
#-- convert amplitude from input units to meters
amplitude = ampl * SCALE
#-- convert phase to degrees
phase = ph * 180.0 / np.pi
phase[phase < 0] += 360.0
#-- return the interpolated values
return (amplitude, phase, D, constituents)
def extract_tidal_constants(ilon,
ilat,
grid_file,
model_file,
EPSG,
TYPE='z',
METHOD='spline',
GRID='OTIS'):
"""
Reads files for an OTIS-formatted tidal model
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Arguments
---------
ilon: longitude to interpolate
ilat: latitude to interpolate
grid_file: grid file for model
model_file: model file containing each constituent
EPSG: projection of tide model data
TYPE: tidal variable to run
z: heights
u: horizontal transport velocities
v: vertical transport velocities
Keyword arguments
-----------------
METHOD: interpolation method
bilinear: quick bilinear interpolation
spline: scipy bivariate spline interpolation
linear, nearest: scipy regular grid interpolations
GRID: binary file type to read
ATLAS: reading a global solution with localized solutions
OTIS: combined global solution
Returns
-------
amplitude: amplitudes of tidal constituents
phase: phases of tidal constituents
D: bathymetry of tide model
constituents: list of model constituents
"""
#-- read the OTIS-format tide grid file
if (GRID == 'ATLAS'):
#-- if reading a global solution with localized solutions
x0, y0, hz0, mz0, iob, dt, pmask, local = read_atlas_grid(grid_file)
xi, yi, hz = combine_atlas_model(x0,
y0,
hz0,
pmask,
local,
VARIABLE='depth')
mz = create_atlas_mask(x0, y0, mz0, local, VARIABLE='depth')
else:
#-- if reading a single OTIS solution
xi, yi, hz, mz, iob, dt = read_tide_grid(grid_file)
#-- adjust dimensions of input coordinates to be iterable
#-- run wrapper function to convert coordinate systems of input lat/lon
x, y = convert_ll_xy(np.atleast_1d(ilon), np.atleast_1d(ilat), EPSG, 'F')
invalid = (x < xi.min()) | (x > xi.max()) | (y < yi.min()) | (y > yi.max())
#-- grid step size of tide model
dx = xi[1] - xi[0]
dy = yi[1] - yi[0]
if (TYPE != 'z'):
mz, mu, mv = Muv(hz)
hu, hv = Huv(hz)
#-- if global: extend limits
GLOBAL = False
#-- replace original values with extend arrays/matrices
if ((xi[-1] - xi[0]) == (360.0 - dx)) & (EPSG == '4326'):
xi = extend_array(xi, dx)
hz = extend_matrix(hz)
mz = extend_matrix(mz)
#-- set global flag
GLOBAL = True
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
if (np.min(x) < np.min(xi)) & (EPSG == '4326'):
lt0, = np.nonzero(x < 0)
x[lt0] += 360.0
if (np.max(x) > np.max(xi)) & (EPSG == '4326'):
gt180, = np.nonzero(x > 180)
x[gt180] -= 360.0
#-- masks zero values
hz = np.ma.array(hz, mask=(hz == 0))
if (TYPE != 'z'):
#-- replace original values with extend matrices
if GLOBAL:
hu = extend_matrix(hu)
hv = extend_matrix(hv)
mu = extend_matrix(mu)
mv = extend_matrix(mv)
#-- masks zero values
hu = np.ma.array(hu, mask=(hu == 0))
hv = np.ma.array(hv, mask=(hv == 0))
#-- interpolate depth and mask to output points
if (METHOD == 'bilinear'):
#-- use quick bilinear to interpolate values
D = bilinear_interp(xi, yi, hz, x, y)
mz1 = bilinear_interp(xi, yi, mz, x, y)
mz1 = np.ceil(mz1).astype(mz.dtype)
if (TYPE != 'z'):
mu1 = bilinear_interp(xi, yi, mu, x, y)
mu1 = np.ceil(mu1).astype(mu.dtype)
mv1 = bilinear_interp(xi, yi, mv, x, y)
mv1 = np.ceil(mv1).astype(mz.dtype)
elif (METHOD == 'spline'):
#-- use scipy bivariate splines to interpolate values
f1 = scipy.interpolate.RectBivariateSpline(xi, yi, hz.T, kx=1, ky=1)
f2 = scipy.interpolate.RectBivariateSpline(xi, yi, mz.T, kx=1, ky=1)
D = f1.ev(x, y)
mz1 = np.ceil(f2.ev(x, y)).astype(mz.dtype)
if (TYPE != 'z'):
f3 = scipy.interpolate.RectBivariateSpline(xi,
yi,
mu.T,
kx=1,
ky=1)
f4 = scipy.interpolate.RectBivariateSpline(xi,
yi,
mv.T,
kx=1,
ky=1)
mu1 = np.ceil(f3.ev(x, y)).astype(mu.dtype)
mv1 = np.ceil(f4.ev(x, y)).astype(mv.dtype)
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator((yi, xi),
hz,
method=METHOD,
bounds_error=False)
r2 = scipy.interpolate.RegularGridInterpolator((yi, xi),
mz,
method=METHOD,
bounds_error=False,
fill_value=0)
D = r1.__call__(np.c_[y, x])
mz1 = np.ceil(r2.__call__(np.c_[y, x])).astype(mz.dtype)
if (TYPE != 'z'):
r3 = scipy.interpolate.RegularGridInterpolator((yi, xi),
mu,
method=METHOD,
bounds_error=False,
fill_value=0)
r4 = scipy.interpolate.RegularGridInterpolator((yi, xi),
mv,
method=METHOD,
bounds_error=False,
fill_value=0)
mu1 = np.ceil(r3.__call__(np.c_[y, x])).astype(mu.dtype)
mv1 = np.ceil(r4.__call__(np.c_[y, x])).astype(mv.dtype)
#-- u and v are velocities in cm/s
if TYPE in ('v', 'u'):
unit_conv = (D / 100.0)
#-- U and V are transports in m^2/s
elif TYPE in ('V', 'U'):
unit_conv = 1.0
#-- read and interpolate each constituent
constituents, nc = read_constituents(model_file)
npts = len(D)
amplitude = np.ma.zeros((npts, nc))
amplitude.mask = np.zeros((npts, nc), dtype=np.bool)
ph = np.ma.zeros((npts, nc))
ph.mask = np.zeros((npts, nc), dtype=np.bool)
for i, c in enumerate(constituents):
if (TYPE == 'z'):
#-- read constituent from elevation file
if (GRID == 'ATLAS'):
z0, zlocal = read_atlas_elevation(model_file, i, c)
xi, yi, z = combine_atlas_model(x0,
y0,
z0,
pmask,
zlocal,
VARIABLE='z')
else:
z = read_elevation_file(model_file, i)
#-- replace original values with extend matrices
if GLOBAL:
z = extend_matrix(z)
#-- interpolate amplitude and phase of the constituent
z1 = np.ma.zeros((npts), dtype=z.dtype)
if (METHOD == 'bilinear'):
#-- replace zero values with nan
z[z == 0] = np.nan
#-- use quick bilinear to interpolate values
z1.data[:] = bilinear_interp(xi,
yi,
z,
x,
y,
dtype=np.complex128)
#-- replace nan values with fill_value
z1.mask = (np.isnan(z1.data) | (~mz1.astype(np.bool)))
z1.data[z1.mask] = z1.fill_value
elif (METHOD == 'spline'):
#-- use scipy bivariate splines to interpolate values
f1 = scipy.interpolate.RectBivariateSpline(xi,
yi,
z.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(xi,
yi,
z.imag.T,
kx=1,
ky=1)
z1.data.real = f1.ev(x, y)
z1.data.imag = f2.ev(x, y)
#-- replace zero values with fill_value
z1.mask = (~mz1.astype(np.bool))
z1.data[z1.mask] = z1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator(
(yi, xi),
z,
method=METHOD,
bounds_error=False,
fill_value=z1.fill_value)
z1 = np.ma.zeros((npts), dtype=z.dtype)
z1.data[:] = r1.__call__(np.c_[y, x])
#-- replace invalid values with fill_value
z1.mask = (z1.data == z1.fill_value) | (~mz1.astype(np.bool))
z1.data[z1.mask] = z1.fill_value
#-- amplitude and phase of the constituent
amplitude.data[:, i] = np.abs(z1.data)
amplitude.mask[:, i] = np.copy(z1.mask)
ph.data[:, i] = np.arctan2(-np.imag(z1.data), np.real(z1.data))
ph.mask[:, i] = np.copy(z1.mask)
elif TYPE in ('U', 'u'):
#-- read constituent from transport file
if (GRID == 'ATLAS'):
u0, v0, uvlocal = read_atlas_transport(model_file, i, c)
xi, yi, u = combine_atlas_model(x0,
y0,
u0,
pmask,
uvlocal,
VARIABLE='u')
else:
u, v = read_transport_file(model_file, i)
#-- replace original values with extend matrices
if GLOBAL:
u = extend_matrix(u)
#-- x coordinates for u transports
xu = xi - dx / 2.0
#-- interpolate amplitude and phase of the constituent
u1 = np.ma.zeros((npts), dtype=u.dtype)
if (METHOD == 'bilinear'):
#-- replace zero values with nan
u[u == 0] = np.nan
#-- use quick bilinear to interpolate values
u1.data[:] = bilinear_interp(xu,
yi,
u,
x,
y,
dtype=np.complex128)
#-- replace nan values with fill_value
u1.mask = (np.isnan(u1.data) | (~mu1.astype(np.bool)))
u1.data[u1.mask] = u1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(xu,
yi,
u.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(xu,
yi,
u.imag.T,
kx=1,
ky=1)
u1.data.real = f1.ev(x, y)
u1.data.imag = f2.ev(x, y)
#-- replace zero values with fill_value
u1.mask = (~mu1.astype(np.bool))
u1.data[u1.mask] = u1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator(
(yi, xu),
u,
method=METHOD,
bounds_error=False,
fill_value=u1.fill_value)
u1.data[:] = r1.__call__(np.c_[y, x])
#-- replace invalid values with fill_value
u1.mask = (u1.data == u1.fill_value) | (~mu1.astype(np.bool))
u1.data[u1.mask] = u1.fill_value
#-- convert units
u1 = u1 / unit_conv
#-- amplitude and phase of the constituent
amplitude.data[:, i] = np.abs(u1)
amplitude.mask[:, i] = np.copy(u1.mask)
ph.data[:, i] = np.arctan2(-np.imag(u1), np.real(u1))
ph.mask[:, i] = np.copy(u1.mask)
elif TYPE in ('V', 'v'):
#-- read constituent from transport file
if (GRID == 'ATLAS'):
u0, v0, uvlocal = read_atlas_transport(model_file, i, c)
xi, yi, v = combine_atlas_model(x0,
y0,
v0,
pmask,
local,
VARIABLE='v')
else:
u, v = read_transport_file(model_file, i)
#-- replace original values with extend matrices
if GLOBAL:
v = extend_matrix(v)
#-- y coordinates for v transports
yv = yi - dy / 2.0
#-- interpolate amplitude and phase of the constituent
v1 = np.ma.zeros((npts), dtype=v.dtype)
if (METHOD == 'bilinear'):
#-- replace zero values with nan
v[v == 0] = np.nan
#-- use quick bilinear to interpolate values
v1.data = bilinear_interp(xi, yv, v, x, y, dtype=np.complex128)
#-- replace nan values with fill_value
v1.mask = (np.isnan(v1.data) | (~mv1.astype(np.bool)))
v1.data[v1.mask] = v1.fill_value
elif (METHOD == 'spline'):
f1 = scipy.interpolate.RectBivariateSpline(xi,
yv,
v.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(xi,
yv,
v.imag.T,
kx=1,
ky=1)
v1.data.real = f1.ev(x, y)
v1.data.imag = f2.ev(x, y)
#-- replace zero values with fill_value
v1.mask = (~mv1.astype(np.bool))
v1.data[v1.mask] = v1.fill_value
else:
#-- use scipy regular grid to interpolate values
r1 = scipy.interpolate.RegularGridInterpolator(
(yv, xi),
v,
method=METHOD,
bounds_error=False,
fill_value=v1.fill_value)
v1.data[:] = r1.__call__(np.c_[y, x])
#-- replace invalid values with fill_value
v1.mask = (v1.data == v1.fill_value) | (~mv1.astype(np.bool))
v1.data[v1.mask] = v1.fill_value
#-- convert units
v1 = v1 / unit_conv
#-- amplitude and phase of the constituent
amplitude.data[:, i] = np.abs(v1)
amplitude.mask[:, i] = np.copy(v1.mask)
ph.data[:, i] = np.arctan2(-np.imag(v1), np.real(v1))
ph.mask[:, i] = np.copy(v1.mask)
#-- update mask to invalidate points outside model domain
ph.mask[:, i] |= invalid
amplitude.mask[:, i] |= invalid
#-- convert phase to degrees
phase = ph * 180.0 / np.pi
phase.data[phase.data < 0] += 360.0
#-- replace data for invalid mask values
amplitude.data[amplitude.mask] = amplitude.fill_value
phase.data[phase.mask] = phase.fill_value
#-- return the interpolated values
return (amplitude, phase, D, constituents)
def extract_GOT_constants(ilon,
ilat,
model_files,
METHOD=None,
EXTRAPOLATE=False,
CUTOFF=10.0,
GZIP=True,
SCALE=1.0):
"""
Reads files for Richard Ray's Global Ocean Tide (GOT) models
Makes initial calculations to run the tide program
Spatially interpolates tidal constituents to input coordinates
Parameters
----------
ilon: float
longitude to interpolate
ilat: float
latitude to interpolate
model_files: list
list of model files for each constituent
METHOD: str, default 'spline'
Interpolation method
- ``'bilinear'``: quick bilinear interpolation
- ``'spline'``: scipy bivariate spline interpolation
- ``'linear'``, ``'nearest'``: scipy regular grid interpolations
EXTRAPOLATE: bool, default False
Extrapolate model using nearest-neighbors
CUTOFF: float, default 10.0
Extrapolation cutoff in kilometers
Set to np.inf to extrapolate for all points
GZIP: bool, default False
Input files are compressed
SCALE: float, default 1.0
Scaling factor for converting to output units
Returns
-------
amplitude: float
amplitudes of tidal constituents
phase: float
phases of tidal constituents
constituents: list
list of model constituents
"""
#-- raise warning if model files are entered as a string
if isinstance(model_files, str):
warnings.warn("Tide model is entered as a string")
model_files = [model_files]
#-- adjust dimensions of input coordinates to be iterable
ilon = np.atleast_1d(ilon)
ilat = np.atleast_1d(ilat)
#-- number of points
npts = len(ilon)
#-- number of constituents
nc = len(model_files)
constituents = []
#-- amplitude and phase
amplitude = np.ma.zeros((npts, nc))
amplitude.mask = np.zeros((npts, nc), dtype=bool)
ph = np.ma.zeros((npts, nc))
ph.mask = np.zeros((npts, nc), dtype=bool)
#-- read and interpolate each constituent
for i, model_file in enumerate(model_files):
#-- check that model file is accessible
if not os.access(os.path.expanduser(model_file), os.F_OK):
raise FileNotFoundError(os.path.expanduser(model_file))
#-- read constituent from elevation file
hc, lon, lat, cons = read_GOT_grid(os.path.expanduser(model_file),
GZIP=GZIP)
#-- append to the list of constituents
constituents.append(cons)
#-- adjust longitudinal convention of input latitude and longitude
#-- to fit tide model convention
if (np.min(ilon) < 0.0) & (np.max(lon) > 180.0):
#-- input points convention (-180:180)
#-- tide model convention (0:360)
ilon[ilon < 0.0] += 360.0
elif (np.max(ilon) > 180.0) & (np.min(lon) < 0.0):
#-- input points convention (0:360)
#-- tide model convention (-180:180)
ilon[ilon > 180.0] -= 360.0
#-- grid step size of tide model
dlon = np.abs(lon[1] - lon[0])
dlat = np.abs(lat[1] - lat[0])
#-- replace original values with extend matrices
lon = extend_array(lon, dlon)
hc = extend_matrix(hc)
#-- interpolated complex form of constituent oscillation
hci = np.ma.zeros((npts), dtype=hc.dtype, fill_value=hc.fill_value)
hci.mask = np.zeros((npts), dtype=bool)
#-- interpolate amplitude and phase of the constituent
if (METHOD == 'bilinear'):
#-- replace invalid values with nan
hc[hc.mask] = np.nan
#-- use quick bilinear to interpolate values
hci.data[:] = bilinear_interp(lon,
lat,
hc,
ilon,
ilat,
dtype=hc.dtype)
#-- replace nan values with fill_value
hci.mask[:] |= np.isnan(hci.data)
hci.data[hci.mask] = hci.fill_value
elif (METHOD == 'spline'):
#-- interpolate complex form of the constituent with scipy
f1 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.data.real.T,
kx=1,
ky=1)
f2 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.data.imag.T,
kx=1,
ky=1)
f3 = scipy.interpolate.RectBivariateSpline(lon,
lat,
hc.mask.T,
kx=1,
ky=1)
hci.data.real[:] = f1.ev(ilon, ilat)
hci.data.imag[:] = f2.ev(ilon, ilat)
hci.mask[:] = f3.ev(ilon, ilat).astype(bool)
#-- replace invalid values with fill_value
hci.data[hci.mask] = hci.fill_value
else:
#-- use scipy regular grid to interpolate values for a given method
r1 = scipy.interpolate.RegularGridInterpolator(
(lat, lon),
hc.data,
method=METHOD,
bounds_error=False,
fill_value=hci.fill_value)
r2 = scipy.interpolate.RegularGridInterpolator((lat, lon),
hc.mask,
method=METHOD,
bounds_error=False,
fill_value=1)
hci.data[:] = r1.__call__(np.c_[ilat, ilon])
hci.mask[:] = np.ceil(r2.__call__(np.c_[ilat, ilon])).astype(bool)
#-- replace invalid values with fill_value
hci.mask[:] |= (hci.data == hci.fill_value)
hci.data[hci.mask] = hci.fill_value
#-- extrapolate data using nearest-neighbors
if EXTRAPOLATE and np.any(hci.mask):
#-- find invalid data points
inv, = np.nonzero(hci.mask)
#-- replace invalid values with nan
hc[hc.mask] = np.nan
#-- extrapolate points within cutoff of valid model points
hci[inv] = nearest_extrap(lon,
lat,
hc,
ilon[inv],
ilat[inv],
dtype=hc.dtype,
cutoff=CUTOFF)
#-- convert amplitude from input units to meters
amplitude.data[:, i] = np.abs(hci.data) * SCALE
amplitude.mask[:, i] = np.copy(hci.mask)
#-- phase of the constituent in radians
ph.data[:, i] = np.arctan2(-np.imag(hci.data), np.real(hci.data))
ph.mask[:, i] = np.copy(hci.mask)
#-- convert phase to degrees
phase = ph * 180.0 / np.pi
phase.data[phase.data < 0] += 360.0
#-- replace data for invalid mask values
amplitude.data[amplitude.mask] = amplitude.fill_value
phase.data[phase.mask] = phase.fill_value
#-- return the interpolated values
return (amplitude, phase, constituents)