#!/usr/bin/env python
from __future__ import absolute_import, division, print_function, \
unicode_literals
from optparse import OptionParser
import xarray
from mpas_tools.io import write_netcdf
[docs]
def translate(mesh, xOffset=0., yOffset=0.):
"""
Translates the coordinate system of the planar MPAS mesh by an arbitrary
shift in x and/or y
Parameters
----------
mesh : xarray.Dataset
A planar mesh to translate
xOffset : float, optional
user-specified shift in the x-direction
yOffset : float, optional
user-specified shift in the y-direction
"""
mesh.xCell[:] += xOffset
mesh.yCell[:] += yOffset
mesh.xVertex[:] += xOffset
mesh.yVertex[:] += yOffset
mesh.xEdge[:] += xOffset
mesh.yEdge[:] += yOffset
def center_on_mesh(mesh, otherMesh):
"""
Translates the coordinate system of the planar MPAS mesh by shifting the
origin to the center of the domain described in a separate mesh
Parameters
----------
mesh : xarray.Dataset
A planar mesh to translate
otherMesh : xarray.Dataset
Another planar mesh whose center will become the center of this mesh.
Uses xCell,yCell or, if those fields do not exist, will secondly try
x1,y1 fields
"""
mpasXcenter, mpasYcenter = get_center(mesh)
if 'xCell' in otherMesh and 'yCell' in otherMesh:
dataXcenter, dataYcenter = get_center(otherMesh, xVar='xCell',
yVar='yCell')
elif 'x1' in otherMesh and 'y1' in otherMesh:
dataXcenter, dataYcenter = get_center(otherMesh, xVar='x1', yVar='y1')
else:
raise ValueError('reference mesh has neither xCell/yCell nor x1/y1 '
'fields.')
translate(mesh, dataXcenter-mpasXcenter, dataYcenter-mpasYcenter)
def center(mesh):
"""
Translates the coordinate system of the planar MPAS mesh by shifting the
origin to the center of the domain
Parameters
----------
mesh : xarray.Dataset
A planar mesh to translate
"""
mpasXcenter, mpasYcenter = get_center(mesh)
translate(mesh, -mpasXcenter, -mpasYcenter)
def get_center(mesh, xVar='xCell', yVar='yCell'):
"""
Find the center of the mesh
"""
xCenter = (mesh[xVar].min() + mesh[xVar].max()) * 0.5
yCenter = (mesh[yVar].min() + mesh[yVar].max()) * 0.5
return xCenter, yCenter
def main():
print("== Gathering information. (Invoke with --help for more details. "
"All arguments are optional)")
parser = OptionParser()
parser.description = \
"This script translates the coordinate system of the planar MPAS " \
"mesh specified with the -f flag. \n" \
"There are 3 possible methods to choose from:\n" \
"1) shift the origin to the center of the domain\n" \
"2) arbirary shift in x and/or y\n" \
"3) shift to the center of the domain described in a separate file\n"
parser.add_option("-f", "--file", dest="fileInName",
help="MPAS planar grid file name.", default="grid.nc",
metavar="FILENAME")
parser.add_option("-d", "--datafile", dest="dataFileName",
help="data file name to which to match the domain "
"center of. Uses xCell,yCell or, if those fields "
"do not exist, will secondly try x1,y1 fields.",
metavar="FILENAME")
parser.add_option("-x", dest="xshift",
help="user-specified shift in the x-direction.",
type="float", default=0.0, metavar="SHIFT_VALUE")
parser.add_option("-y", dest="yshift",
help="user-specified shift in the y-direction.",
type="float", default=0.0, metavar="SHIFT_VALUE")
parser.add_option("-c", dest="center",
help="shift so origin is at center of domain",
action="store_true", default=False)
for option in parser.option_list:
if option.default != ("NO", "DEFAULT"):
option.help += (" " if option.help else "") + "[default: %default]"
options, args = parser.parse_args()
print("Attempting to translate coordinates in file: {}".format(
options.fileInName))
if options.dataFileName is not None and \
(options.xshift != 0. or options.yshift != 0.):
raise ValueError('Specifying a datafile AND one or both of x/y shift '
'is invalid. Please select one of those methods '
'only.')
if options.center and (options.xshift != 0. or options.yshift != 0.):
raise ValueError('Specifying a shift to center AND one or both of x/y '
'shift is invalid. Please select one of those '
'methods only.')
if options.dataFileName is not None and options.center:
raise ValueError('Specifying a datafile AND a shift to center is '
'invalid. Please select one of those methods only.')
if not options.center and (options.xshift == 0.) and \
(options.yshift == 0.) and options.dataFileName is None:
raise ValueError('No translation method was specified. Please select '
'one. Run with -h for more information.')
mesh = xarray.open_dataset(options.fileInName)
if options.dataFileName is not None:
print(" Translating coordinates in {} so the domain center matches "
"the domain center in {}.\n\n".format(options.fileInName,
options.dataFileName))
otherMesh = xarray.open_dataset(options.dataFileName)
center_on_mesh(mesh, otherMesh)
if options.xshift != 0. or options.yshift != 0.:
print(" Translating coordinates in {} by user-specified values. "
"X-shift={:f}; Y-shift={:f}\n\n".format(options.fileInName,
options.xshift,
options.yshift))
translate(mesh, options.xshift, options.yshift)
if options.center:
print(" Translating coordinates in %s so the origin is the center of "
"the domain.\n\n")
center(mesh)
# close the file so we can re-open it for writing
mesh.close()
write_netcdf(mesh, options.fileInName)
print("Translation completed.")
if __name__ == '__main__':
main()