#!/usr/bin/env python
# Simple script to inject mesh density onto a mesh
# example usage:
# ./inject_meshDensity.py cellWidthVsLatLon.nc base_mesh.nc
# where:
# cellWidthVsLatLon.nc is a netcdf file with cellWidth
# base_mesh.nc is the mpas netcdf file where meshDensity is added
# Mark Petersen, 7/24/2018
from __future__ import absolute_import, division, print_function, \
unicode_literals
import numpy as np
import netCDF4 as nc4
import sys
from mpas_tools.mesh.interpolation import interp_bilin
[docs]def inject_meshDensity_from_file(cw_filename, mesh_filename, on_sphere=True):
"""
Add a ``meshDensity`` field into an MPAS mesh. The mesh density is defined
as:
meshDensity = (minCellWidth / cellWidth)**4
Parameters
----------
cw_filename : str
The file name to read ``cellWidth`` and coordinates from
mesh_filename : str
The mesh file to add ``meshDensity`` to
on_sphere : bool, optional
Whether the mesh is spherical (as opposed to planar)
"""
print('Read cell width field from nc file regular grid...')
ds = nc4.Dataset(cw_filename,'r')
cellWidth = ds.variables['cellWidth'][:]
if on_sphere:
lon = ds.variables['lon'][:]
lat = ds.variables['lat'][:]
ds.close()
inject_spherical_meshDensity(cellWidth, lon, lat, mesh_filename)
else:
x = ds.variables['x'][:]
y = ds.variables['y'][:]
ds.close()
inject_spherical_meshDensity(cellWidth, x, y, mesh_filename)
[docs]def inject_spherical_meshDensity(cellWidth, lon, lat, mesh_filename):
"""
Add a ``meshDensity`` field into a spherical MPAS mesh. The mesh density is
defined as:
meshDensity = (minCellWidth / cellWidth)**4
Parameters
----------
cellWidth : ndarray
m x n array of cell width in km
lon : ndarray
longitude in degrees (length n and between -180 and 180)
lat : ndarray
longitude in degrees (length m and between -90 and 90)
mesh_filename : str
The mesh file to add ``meshDensity`` to
"""
minCellWidth = cellWidth.min()
meshDensityVsXY = (minCellWidth / cellWidth)**4
print(' minimum cell width in grid definition: {0:.0f} km'.format(
minCellWidth))
print(' maximum cell width in grid definition: {0:.0f} km'.format(
cellWidth.max()))
print('Open unstructured MPAS mesh file...')
ds = nc4.Dataset(mesh_filename, 'r+')
meshDensity = ds.variables['meshDensity']
lonCell = ds.variables['lonCell'][:]
latCell = ds.variables['latCell'][:]
lonCell = np.mod(np.rad2deg(lonCell) + 180., 360.) - 180.
latCell = np.rad2deg(latCell)
print('Interpolating and writing meshDensity...')
mpasMeshDensity = interp_bilin(lon, lat, meshDensityVsXY, lonCell, latCell)
meshDensity[:] = mpasMeshDensity
ds.close()
[docs]def inject_planar_meshDensity(cellWidth, x, y, mesh_filename):
"""
Add a ``meshDensity`` field into a planar MPAS mesh. The mesh density is
defined as:
meshDensity = (minCellWidth / cellWidth)**4
Parameters
----------
cellWidth : ndarray
m x n array of cell width in km
x, y : ndarray
Planar coordinates in meters
mesh_filename : str
The mesh file to add ``meshDensity`` to
"""
minCellWidth = cellWidth.min()
meshDensityVsXY = (minCellWidth / cellWidth)**4
print(' minimum cell width in grid definition: {0:.0f} km'.format(minCellWidth))
print(' maximum cell width in grid definition: {0:.0f} km'.format(cellWidth.max()))
print('Open unstructured MPAS mesh file...')
ds = nc4.Dataset(mesh_filename, 'r+')
meshDensity = ds.variables['meshDensity']
xCell = ds.variables['xCell'][:]
yCell = ds.variables['xCell'][:]
print('Interpolating and writing meshDensity...')
mpasMeshDensity = interp_bilin(x, y, meshDensityVsXY, xCell, yCell)
meshDensity[:] = mpasMeshDensity
ds.close()
if __name__ == "__main__":
inject_meshDensity_from_file(cw_filename=sys.argv[1],
mesh_filename=sys.argv[2])