In [1]:
import warnings
import iris
url = 'http://crow.marine.usf.edu:8080/thredds/dodsC/FVCOM-Nowcast-Agg.nc'
with warnings.catch_warnings():
warnings.simplefilter("ignore")
cubes = iris.load_raw(url)
In [2]:
salt = cubes.extract_strict('sea_water_salinity')[-1, ...] # Last time step.
lon = salt.coord(axis='X').points
lat = salt.coord(axis='Y').points
In [3]:
p = salt.coord('sea_surface_height_above_reference_ellipsoid').points
q = salt.data
In [4]:
import numpy as np
from ciso import zslice
p0 = -25
isoslice = zslice(q, p, -25)
In [5]:
import numpy.ma as ma
# For some reason I cannot tricontourf with NaNs.
isoslice = ma.masked_invalid(isoslice)
vmin, vmax = isoslice.min(), isoslice.max()
isoslice = isoslice.filled(fill_value=-999)
In [6]:
%matplotlib inline
import matplotlib.pyplot as plt
import cartopy.crs as ccrs
from cartopy.io import shapereader
from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER
cmap = plt.cm.viridis
def make_map(projection=ccrs.PlateCarree()):
fig, ax = plt.subplots(figsize=(9, 13),
subplot_kw=dict(projection=projection))
gl = ax.gridlines(draw_labels=True)
gl.xlabels_top = gl.ylabels_right = False
gl.xformatter = LONGITUDE_FORMATTER
gl.yformatter = LATITUDE_FORMATTER
ax.coastlines('50m')
return fig, ax
In [7]:
import pyugrid
import matplotlib.tri as tri
ugrid = pyugrid.UGrid.from_ncfile(url)
lon = ugrid.nodes[:, 0]
lat = ugrid.nodes[:, 1]
triangles = ugrid.faces[:]
triang = tri.Triangulation(lon, lat, triangles=triangles)
In [8]:
cmap
Out[8]:
In [9]:
fig, ax = make_map()
extent = [lon.min(), lon.max(),
lat.min(), lat.max()]
ax.set_extent(extent)
levels = np.linspace(vmin, vmax, 20)
kw = dict(cmap=cmap, alpha=0.9, levels=levels)
cs = ax.tricontourf(triang, isoslice, **kw)
kw = dict(shrink=0.5, orientation='vertical')
cbar = fig.colorbar(cs, **kw)