def _subdivide_observations(self, dsObs): # {{{
'''
Subdivide each segment of the transect so the horizontal resolution
approximately matches the requested resolution
'''
lat = dsObs.lat.values
lon = dsObs.lon.values
# compute the great circle distance between these points
dxIn = self._haversine(lon[0:-1], lat[0:-1], lon[1:], lat[1:])
nSegments = numpy.maximum(
(dxIn / self.horizontalResolution + 0.5).astype(int), 1)
xIn = numpy.zeros(lat.shape)
xIn[1:] = numpy.cumsum(dxIn)
outIndex = []
for index in range(len(xIn) - 1):
n = nSegments[index]
outIndex.extend(index + numpy.arange(0, n) / n)
outIndex.append(len(xIn) - 1)
xOut = numpy.interp(outIndex, numpy.arange(len(xIn)), xIn)
dsObs['xIn'] = (('nPoints', ), xIn)
dsObs['xOut'] = (('nPointsOut', ), xOut)
# interpolate fields without and with vertical dimension
dsObs = interp_1d(dsObs,
inInterpDim='nPoints',
inInterpCoord='xIn',
outInterpDim='nPointsOut',
outInterpCoord='xOut')
dsObs = dsObs.drop(['xIn'])
dsObs = dsObs.rename({'nPointsOut': 'nPoints', 'xOut': 'x'})
return dsObs # }}}
def _vertical_interp(self, ds, transectIndex, dsObs, outFileName,
outObsFileName):
'''
Vertically interpolate a transect and write it to a unique file
Parameters
----------
ds : ``xarray.Dataset``
The data set containing all transects before vertical interpolation
transectIndex : int
The index of the transect to extract
dsObs : ``xarray.Dataset``
The obs dataset used if verticalComparisonGridName is 'obs'
outFileName : str
The name of the file to which the resulting data set should be
written
outObsFileName : str
The name of the file to which the resulting obs data set should be
written if it is interpolated
'''
# Authors
# -------
# Xylar Asay-Davis
if os.path.exists(outFileName):
return
ds = ds.where(ds.transectNumber == transectIndex, drop=True)
if self.verticalComparisonGridName == 'mpas':
z = ds.zMid
z = z.rename({'nVertLevels': 'nzOut'})
elif self.verticalComparisonGridName == 'obs':
z = dsObs.z
z = z.rename({'nz': 'nzOut'})
else:
# a defined vertical grid
z = (('nzOut', ), self.verticalComparisonGrid)
if self.verticalComparisonGridName == 'mpas':
ds = ds.rename({'zMid': 'z', 'nVertLevels': 'nz'})
else:
ds['z'] = z
# remap each variable
ds = interp_1d(ds,
inInterpDim='nVertLevels',
inInterpCoord='zMid',
outInterpDim='nzOut',
outInterpCoord='z')
ds = ds.rename({'nzOut': 'nz'})
if self.verticalComparisonGridName != 'obs' and 'nz' in dsObs.dims:
dsObs['zOut'] = z
# remap each variable
dsObs = interp_1d(dsObs,
inInterpDim='nz',
inInterpCoord='z',
outInterpDim='nzOut',
outInterpCoord='zOut')
dsObs = dsObs.rename({'nzOut': 'nz'})
write_netcdf(dsObs, outObsFileName)
ds = ds.drop(['validMask', 'transectNumber'])
write_netcdf(ds, outFileName) # }}}