def main():
p = ArgumentParser(description="calls IGRF from Python, and plots "
"the modeled geomagnetic field")
p.add_argument("date",
help="date of sim",
nargs="?",
default=datetime.date.today())
p.add_argument("--isv",
help="0: main field. 1: secular variation",
type=int,
default=0)
p.add_argument("--itype",
help="1: geodetic. 2: geocentric",
type=int,
default=1)
p.add_argument(
"-a",
"--altkm",
help="(km) above sea level if itype=1,"
" (km) from center of Earth if itype=2",
type=float,
nargs="+",
default=0,
)
p.add_argument("-c",
"--latlon",
help="geodetic latitude, longitude (deg)",
type=float,
nargs=2)
P = p.parse_args()
# do world-wide grid if no user input
if not P.altkm or not P.latlon:
glat, glon = igrf12.latlonworldgrid()
elif P.altkm and P.latlon:
glat, glon = P.latlon
else:
raise ValueError("please input all 3 of lat,lon,alt or none of them")
mag12: xarray.Dataset = igrf12.gridigrf12(P.date, glat, glon, P.altkm,
P.isv, P.itype)
# mag11 = igrf12.testigrf11(p.date,glat,glon,p.altkm, p.isv, p.itype)
if glat.ndim == 2:
plt.plotigrf(mag12, "12")
# plt.plotdiff1112(mag12,mag11)
else:
print(mag12)
show()
def main():
p = ArgumentParser(description='calls IGRF from Python, and plots '
'the modeled geomagnetic field')
p.add_argument('date', help='date of sim', nargs='?',
default=datetime.date.today())
p.add_argument('--isv', help='0: main field. 1: secular variation',
type=int, default=0)
p.add_argument('--itype', help='1: geodetic. 2: geocentric', type=int,
default=1)
p.add_argument('-a', '--altkm',
help='(km) above sea level if itype=1,'
' (km) from center of Earth if itype=2', type=float,
nargs='+', default=0)
p.add_argument('-c', '--latlon', help='geodetic latitude, longitude (deg)',
type=float, nargs=2)
P = p.parse_args()
# do world-wide grid if no user input
if not P.altkm or not P.latlon:
glat, glon = igrf12.latlonworldgrid()
elif P.altkm and P.latlon:
glat, glon = P.latlon
else:
raise ValueError('please input all 3 of lat,lon,alt or none of them')
mag12: xarray.Dataset = igrf12.gridigrf12(P.date, glat, glon, P.altkm,
P.isv, P.itype)
# mag11 = igrf12.testigrf11(p.date,glat,glon,p.altkm, p.isv, p.itype)
if glat.ndim == 2:
plt.plotigrf(mag12, '12')
# plt.plotdiff1112(mag12,mag11)
else:
print(mag12)
show()
def plotCartoMap(latlim=None, lonlim=None, parallels=None, meridians=None,
pole_center_lon=0, figsize=(12, 8), terrain=False, ax=False,
projection='stereo', title='', resolution='110m',
states=True, grid_linewidth=0.5, grid_color='black',
grid_linestyle='--', background_color=None, border_color='k',
figure=False, nightshade=False, ns_dt=None, ns_alpha=0.1,
apex=False, igrf=False, date=None,
mlat_levels=None, mlon_levels=None, alt_km=0.0,
mlon_colors='blue', mlat_colors='red', mgrid_width=1,
mgrid_labels=True, mgrid_fontsize=12, mlon_cs='mlon',
incl_levels=None, decl_levels=None, igrf_param='incl',
mlon_labels=True, mlat_labels=True, mgrid_style='--',
label_colors='k',
decl_colors='k', incl_colors='k'):
if lonlim is None:
if projection in ['southpole', 'northpole']:
lonlim = [-180, 180]
else:
lonlim = [-40, 40]
if latlim is None:
if projection is'southpole':
latlim = [-90, 0]
elif projection is 'northpole':
latlim = [90, 0]
else:
latlim = [0, 75]
STATES = cfeature.NaturalEarthFeature(
category='cultural',
name='admin_1_states_provinces_lines',
scale='50m',
facecolor='none')
if not ax:
if figsize is None:
fig = plt.figure()
else:
fig = plt.figure(figsize=figsize)
if projection == 'stereo':
ax = plt.axes(projection=ccrs.Stereographic(central_longitude=(sum(lonlim) / 2)))
elif projection == 'merc':
ax = plt.axes(projection=ccrs.Mercator())
elif projection == 'plate':
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=(sum(lonlim) / 2)))
elif projection == 'lambert':
ax = plt.axes(projection=ccrs.LambertConformal(central_longitude=(sum(lonlim) / 2),
central_latitude=(sum(latlim) / 2)))
elif projection == 'mollweide':
ax = plt.axes(projection=ccrs.Mollweide(central_longitude=(sum(lonlim) / 2)))
elif projection == 'northpole':
ax = plt.axes(projection=ccrs.NorthPolarStereo())
ax.set_boundary(circle, transform=ax.transAxes)
# polarLim(ax, projection)
elif projection == 'southpole':
ax = plt.axes(projection=ccrs.SouthPolarStereo())
ax.set_boundary(circle, transform=ax.transAxes)
# polarLim(ax, projection)
if background_color is not None:
ax.background_patch.set_facecolor(background_color)
ax.set_title(title)
ax.coastlines(color=border_color, resolution=resolution) # 110m, 50m or 10m
if states:
ax.add_feature(STATES, edgecolor=border_color)
ax.add_feature(cfeature.BORDERS, edgecolor=border_color)
if terrain:
ax.stock_img()
if nightshade:
assert ns_dt is not None
assert ns_alpha is not None
ax.add_feature(Nightshade(ns_dt, ns_alpha))
# Draw Parallels
if projection == 'merc' or projection == 'plate':
if isinstance(meridians, np.ndarray):
meridians = list(meridians)
if isinstance(parallels, np.ndarray):
parallels = list(parallels)
gl = ax.gridlines(crs=ccrs.PlateCarree(), color=grid_color, draw_labels=False,
linestyle=grid_linestyle, linewidth=grid_linewidth)
if meridians is None:
gl.xlines = False
else:
if len(meridians) > 0:
gl.xlocator = mticker.FixedLocator(meridians)
gl.xlabels_bottom = True
else:
gl.ylines = False
if parallels is None:
gl.ylines = False
else:
if len(parallels) > 0:
gl.ylocator = mticker.FixedLocator(parallels)
# ax.yaxis.set_major_formatter(LONGITUDE_FORMATTER)
gl.ylabels_left = True
else:
gl.ylines = False
else:
gl = ax.gridlines(crs=ccrs.PlateCarree(), color=grid_color, draw_labels=False,
linestyle=grid_linestyle, linewidth=grid_linewidth)
if meridians is None:
gl.xlines = False
else:
# if isinstance(meridians, np.ndarray):
# meridians = list(meridians)
# ax.xaxis.set_major_formatter(LONGITUDE_FORMATTER)
# ax.yaxis.set_major_formatter(LATITUDE_FORMATTER)
# if isinstance(meridians, np.ndarray):
# meridians = list(meridians)
gl.xlocator = mticker.FixedLocator(meridians)
# else:
# gl.xlines = False
if parallels is not None:
if isinstance(parallels, np.ndarray):
parallels = list(parallels)
gl.ylocator = mticker.FixedLocator(parallels)
else:
gl.ylines = False
# Geomagnetic coordinates @ Apex
if apex:
if date is None:
date = datetime(2017, 12, 31, 0, 0, 0)
assert isinstance(date, datetime)
A = ap.Apex(date=date)
# Define levels and ranges for conversion
if mlon_cs == 'mlt':
if mlon_levels is None:
mlon_levels = np.array([])
mlon_range = np.arange(0, 24.1, 0.1)
elif isinstance(mlon_levels, bool):
if mlon_levels == False:
mlon_levels = np.array([])
mlon_range = np.arange(0, 24.1, 0.1)
else:
mlon_range = np.arange(mlon_levels[0], mlon_levels[-1] + 0.1, 0.1)
else:
if mlon_levels is None:
mlon_levels = np.array([])
mlon_range = np.arange(-180, 180, 0.5)
elif isinstance(mlon_levels, bool):
if mlon_levels == False:
mlon_levels = np.array([])
mlon_range = np.arange(-180, 181, 0.1)
else:
mlon_range = np.arange(mlon_levels[0], mlon_levels[0] + 362, 0.1)
if mlat_levels is None:
mlat_levels = np.arange(-90, 90.1, 5)
mlat_range = np.arange(mlat_levels[0], mlat_levels[-1] + 0.1, 0.1)
# Do meridans
for mlon in mlon_levels:
MLON = mlon * np.ones(mlat_range.size)
if mlon_cs == 'mlt':
y, x = A.convert(mlat_range, MLON, 'mlt', 'geo', datetime=date)
else:
y, x = A.convert(mlat_range, MLON, 'apex', 'geo')
# Plot meridian
inmap = np.logical_and(x >= lonlim[0], x <= lonlim[1])
if np.sum(inmap) > 10:
ax.plot(np.unwrap(x, 180), np.unwrap(y, 90), c=mlon_colors,
lw=mgrid_width, linestyle=mgrid_style,
transform=ccrs.PlateCarree())
# Labels
if mlon_labels:
ix = np.argmin(abs(y - np.mean(latlim)))
mx = x[ix] - 1 if mlon >= 10 else x[ix] - 0.5
my = np.mean(latlim)
if np.logical_and(mx >= lonlim[0], mx <= lonlim[1]):
if mlon_cs == 'mlt' and mlon != 0:
ax.text(mx, my, str(int(mlon)), color=label_colors,
fontsize=14, backgroundcolor='white',
transform=ccrs.PlateCarree())
elif mlon_cs != 'mlt' and mlon != 360:
ax.text(mx, my, str(int(mlon)), color=label_colors,
fontsize=14, backgroundcolor='white',
transform=ccrs.PlateCarree())
# Do parallels
for mlat in mlat_levels:
MLAT = mlat * np.ones(mlon_range.size)
if mlon_cs == 'mlt':
gy, gx = A.convert(MLAT, mlon_range, 'mlt', 'geo', datetime=date)
else:
gy, gx = A.convert(MLAT, mlon_range, 'apex', 'geo', datetime=date)
inmap = np.logical_and(gy >= latlim[0], gy <= latlim[1])
if np.sum(inmap) > 2:
ax.plot(np.unwrap(gx, 180), np.unwrap(gy, 90), c=mlat_colors,
lw=mgrid_width, linestyle=mgrid_style,
transform=ccrs.PlateCarree())
# Labels
if mlat_labels:
ix = np.argmin(abs(gx - np.mean(lonlim)))
mx = np.mean(lonlim)
my = gy[ix] - 0.5
if np.logical_and(mx >= lonlim[0], mx <= lonlim[1]) and \
np.logical_and(my >= latlim[0], my <= latlim[1]):
ax.text(mx, my, str(int(mlat)), color=label_colors,
fontsize=14, backgroundcolor='white',
transform=ccrs.PlateCarree())
if igrf:
glon = np.arange(lonlim[0] - 40, lonlim[1] + 40.1, 0.5)
glat = np.arange(-90, 90 + 0.1, 0.5)
longrid, latgrid = np.meshgrid(glon, glat)
mag = igrf12.gridigrf12(t=date, glat=latgrid, glon=longrid, alt_km=alt_km)
if decl_levels is not None:
z = mag.decl.values
for declination in decl_levels:
ax.contour(longrid, latgrid, z, levels=declination,
colors=decl_colors, transform=ccrs.PlateCarree())
if incl_levels is not None:
z = mag.incl.values
for inclination in incl_levels:
ax.contour(longrid, latgrid, z, levels=declination,
colors=incl_colors, transform=ccrs.PlateCarree())
# Set Extent
ax.set_extent([lonlim[0], lonlim[1], latlim[0], latlim[1]], crs=ccrs.PlateCarree())
if 'fig' in locals():
return fig, ax
else:
return ax
def plotCartoMap(latlim=[0, 75],
lonlim=[-40, 40],
parallels=None,
meridians=None,
pole_center_lon=0,
figsize=(12, 8),
terrain=False,
ax=False,
projection='stereo',
title='',
resolution='110m',
lon0=None,
lat0=None,
states=True,
grid_linewidth=0.5,
grid_color='black',
grid_linestyle='--',
background_color=None,
border_color='k',
figure=False,
nightshade=False,
ns_alpha=0.1,
apex=False,
igrf=False,
date=None,
mlat_levels=None,
mlon_levels=None,
alt_km=0.0,
mlon_colors='blue',
mlat_colors='red',
mgrid_width=1,
mgrid_labels=True,
mgrid_fontsize=12,
mlon_cs='mlon',
incl_levels=None,
decl_levels=None,
igrf_param='incl',
mlon_labels=True,
mlat_labels=True,
mgrid_style='--',
label_colors='k',
apex_alt=0,
decl_colors='k',
incl_colors='k',
terminator=False,
terminator_altkm=350,
polarization_terminator=False,
pt_hemisphere='north',
ter_color='red',
ter_style='--',
ter_width=2,
midnight=False,
midnight_colors='m',
midnight_width=2,
midnight_style='--'):
if lonlim is None or lonlim == []:
lonlim = [-180, 180]
STATES = cfeature.NaturalEarthFeature(
category='cultural',
name='admin_1_states_provinces_lines',
scale='50m',
facecolor='none')
if not ax:
if figsize is None:
fig = plt.figure()
else:
fig = plt.figure(figsize=figsize)
if projection == 'stereo':
ax = plt.axes(projection=ccrs.Stereographic(
central_longitude=(sum(lonlim) / 2)))
elif projection == 'merc':
ax = plt.axes(projection=ccrs.Mercator())
elif projection == 'plate':
ax = plt.axes(projection=ccrs.PlateCarree(
central_longitude=(sum(lonlim) / 2)))
elif projection == 'lambert':
ax = plt.axes(projection=ccrs.LambertConformal(
central_longitude=(sum(lonlim) / 2),
central_latitude=(sum(latlim) / 2)))
elif projection == 'mollweide':
ax = plt.axes(projection=ccrs.Mollweide(
central_longitude=(sum(lonlim) / 2)))
elif projection == 'north':
if lon0 is None:
lon0 = 0
ax = plt.axes(projection=ccrs.NorthPolarStereo(
central_longitude=lon0))
elif projection == 'south':
if lon0 is None:
lon0 = 0
ax = plt.axes(projection=ccrs.SouthPolarStereo(
central_longitude=lon0))
elif projection == 'ortographic':
if lon0 is None:
lon0 = 0
if lat0 is None:
lat0 = 0
ax = plt.axes(projection=ccrs.Orthographic(central_longitude=lon0,
central_latitude=lat0))
else:
print("Projection is invalid. Please enter the right one. \n \
'stereo', 'merc', 'plate', 'lambret', mollweide', 'north, 'south', 'ortographic'"
)
return 0
if background_color is not None:
ax.background_patch.set_facecolor(background_color)
ax.set_title(title)
ax.coastlines(color=border_color,
resolution=resolution) # 110m, 50m or 10m
if states:
ax.add_feature(STATES, edgecolor=border_color)
ax.add_feature(cfeature.BORDERS, edgecolor=border_color)
if terrain:
ax.stock_img()
if nightshade:
assert date is not None
assert ns_alpha is not None
ax.add_feature(Nightshade(date, ns_alpha))
# Draw Parralels
if projection == 'merc' or projection == 'plate':
if isinstance(meridians, np.ndarray):
meridians = list(meridians)
if isinstance(parallels, np.ndarray):
parallels = list(parallels)
gl = ax.gridlines(crs=ccrs.PlateCarree(),
color=grid_color,
draw_labels=False,
linestyle=grid_linestyle,
linewidth=grid_linewidth)
if meridians is None:
gl.xlines = False
else:
if len(meridians) > 0:
gl.xlocator = mticker.FixedLocator(meridians)
gl.xlabels_bottom = True
else:
gl.ylines = False
if parallels is None:
gl.ylines = False
else:
if len(parallels) > 0:
gl.ylocator = mticker.FixedLocator(parallels)
gl.ylabels_left = True
else:
gl.ylines = False
else:
gl = ax.gridlines(crs=ccrs.PlateCarree(),
color=grid_color,
draw_labels=False,
linestyle=grid_linestyle,
linewidth=grid_linewidth)
if meridians is None:
gl.xlines = False
else:
gl.xlocator = mticker.FixedLocator(meridians)
if parallels is not None:
if isinstance(parallels, np.ndarray):
parallels = list(parallels)
gl.ylocator = mticker.FixedLocator(parallels)
else:
gl.ylines = False
# Geomagnetic coordinates @ Apex
if apex:
if date is None:
date = datetime(2017, 12, 31, 0, 0, 0)
assert isinstance(date, datetime)
A = ap.Apex(date=date)
# Define levels and ranges for conversion
if mlon_cs == 'mlt':
if mlon_levels is None:
mlon_levels = np.array([])
mlon_range = np.arange(0, 24.01, 0.01)
elif isinstance(mlon_levels, bool):
if mlon_levels == False:
mlon_levels = np.array([])
mlon_range = np.arange(0, 24.01, 0.01)
else:
mlon_range = np.arange(mlon_levels[0], mlon_levels[-1] + 0.1,
0.01)
else:
if mlon_levels is None:
mlon_levels = np.array([])
mlon_range = np.arange(-180, 180, 0.5)
elif isinstance(mlon_levels, bool):
if mlon_levels == False:
mlon_levels = np.array([])
mlon_range = np.arange(-180, 181, 0.1)
else:
mlon_range = np.arange(mlon_levels[0], mlon_levels[0] + 362,
0.1)
if mlat_levels is None:
mlat_levels = np.arange(-90, 90.1, 1)
mlat_range = np.arange(mlat_levels[0], mlat_levels[-1] + 0.1, 0.1)
# Do meridans
for mlon in mlon_levels:
MLON = mlon * np.ones(mlat_range.size)
if mlon_cs == 'mlt':
y, x = A.convert(mlat_range,
MLON,
'mlt',
'geo',
datetime=date,
height=apex_alt)
else:
y, x = A.convert(mlat_range,
MLON,
'apex',
'geo',
height=apex_alt)
mlat_mask_extent = (y >= latlim[0] + 0.2) & (y <= latlim[1] - 0.2)
# Plot meridian
inmap = np.logical_and(x >= lonlim[0], x <= lonlim[1])
if np.sum(inmap) > 10:
ax.plot(np.unwrap(x[mlat_mask_extent], 180),
np.unwrap(y[mlat_mask_extent], 90),
c=mlon_colors,
lw=mgrid_width,
linestyle=mgrid_style,
zorder=90,
transform=ccrs.PlateCarree())
# Labels
if mlon_labels:
ix = abs(y - np.mean(latlim)).argmin()
mx = x[ix] - 1 if mlon >= 10 else x[ix] - 0.5
my = np.mean(latlim)
if np.logical_and(mx >= lonlim[0], mx <= lonlim[1]):
if mlon_cs == 'mlt' and mlon != 0:
ax.text(mx,
my,
str(int(mlon)),
color=label_colors,
fontsize=14,
backgroundcolor='white',
transform=ccrs.PlateCarree())
elif mlon_cs != 'mlt' and mlon != 360:
ax.text(mx,
my,
str(int(mlon)),
color=label_colors,
fontsize=14,
backgroundcolor='white',
transform=ccrs.PlateCarree())
# Do parallels
for mlat in mlat_levels:
MLAT = mlat * np.ones(mlon_range.size)
if mlon_cs == 'mlt':
gy, gx = A.convert(MLAT,
mlon_range,
'mlt',
'geo',
datetime=date,
height=apex_alt)
else:
gy, gx = A.convert(MLAT,
mlon_range,
'apex',
'geo',
datetime=date,
height=apex_alt)
inmap = np.logical_and(gy >= latlim[0], gy <= latlim[1])
if np.sum(inmap) > 20:
ax.plot(np.unwrap(gx, 180),
np.unwrap(gy, 90),
c=mlat_colors,
lw=mgrid_width,
linestyle=mgrid_style,
zorder=90,
transform=ccrs.PlateCarree())
# Labels
if mlat_labels:
ix = abs(gx - np.mean(lonlim)).argmin()
mx = np.mean(lonlim)
my = gy[ix] - 0.5
if np.logical_and(mx >= lonlim[0], mx <= lonlim[1]) and \
np.logical_and(my >= latlim[0], my <= latlim[1]):
ax.text(mx,
my,
str(int(mlat)),
color=label_colors,
fontsize=14,
backgroundcolor='white',
transform=ccrs.PlateCarree())
if igrf:
glon = np.arange(lonlim[0] - 40, lonlim[1] + 40.1, 0.5)
glat = np.arange(-90, 90 + 0.1, 0.5)
longrid, latgrid = np.meshgrid(glon, glat)
mag = igrf12.gridigrf12(t=date,
glat=latgrid,
glon=longrid,
alt_km=alt_km)
if decl_levels is not None:
z = mag.decl.values
for declination in decl_levels:
ax.contour(longrid,
latgrid,
z,
levels=declination,
zorder=90,
colors=decl_colors,
transform=ccrs.PlateCarree())
if incl_levels is not None:
z = mag.incl.values
for inclination in incl_levels:
ax.contour(longrid,
latgrid,
z,
levels=declination,
zorder=90,
colors=incl_colors,
transform=ccrs.PlateCarree())
# Terminators
if terminator:
assert date is not None
if not isinstance(terminator_altkm, list):
terminator_altkm = [terminator_altkm]
for takm in terminator_altkm:
try:
glon_ter, glat_ter = ter.get_terminator(date, alt_km=takm)
if glon_ter is not None and glat_ter is not None:
if isinstance(glon_ter, list):
for i in range(len(glon_ter)):
ax.plot(np.unwrap(glon_ter[i], 180),
np.unwrap(glat_ter[i], 90),
c=ter_color,
lw=ter_width,
ls=ter_style,
zorder=90,
transform=ccrs.PlateCarree())
else:
ax.plot(np.unwrap(glon_ter, 180),
np.unwrap(glat_ter, 90),
c=ter_color,
lw=ter_width,
ls=ter_style,
zorder=90,
transform=ccrs.PlateCarree())
except:
pass
if midnight:
mlat_range = np.arange(-89.9, 90.1, 0.1)
MLON = 0 * np.ones(mlat_range.size)
if mlon_cs == 'mlt':
y, x = A.convert(mlat_range,
MLON,
'mlt',
'geo',
datetime=date,
height=apex_alt)
else:
y, x = A.convert(mlat_range, MLON, 'apex', 'geo', height=apex_alt)
mlat_mask_extent = (y >= latlim[0] + 0.2) & (y <= latlim[1] - 0.2)
# Plot meridian
inmap = np.logical_and(x >= lonlim[0], x <= lonlim[1])
if np.sum(inmap) > 10:
ax.plot(np.unwrap(x[mlat_mask_extent], 180),
np.unwrap(y[mlat_mask_extent], 90),
c=midnight_colors,
lw=midnight_width,
linestyle=midnight_style,
zorder=90,
transform=ccrs.PlateCarree())
# Set Extent
if projection == 'north' or projection == 'south':
import matplotlib.path as mpath
ax.set_extent([-180, 181, latlim[0], latlim[1]],
crs=ccrs.PlateCarree())
theta = np.linspace(0, 2 * np.pi, 100)
center, radius = [0.5, 0.5], 0.5
verts = np.vstack([np.sin(theta), np.cos(theta)]).T
circle = mpath.Path(verts * radius + center)
ax.set_boundary(circle, transform=ax.transAxes)
elif lonlim[0] != -180 and lonlim[1] != 180:
ax.set_extent([lonlim[0], lonlim[1], latlim[0], latlim[1]],
crs=ccrs.PlateCarree()) #ccrs.PlateCarree())
if 'fig' in locals():
return fig, ax
else:
return ax
fig = gm.plotCartoMap(
projection='stereo',
title='Magnetic declination angle. Ground (solid), 150 km (dashed)',
latlim=latlim,
lonlim=lonlim,
parallels=[20, 40, 60, 80, 90],
meridians=[-220, -180, -160, -140, -120, -100, -80, -60, -40, 0],
grid_linewidth=1,
figure=True,
states=False)
glon = np.arange(0, 360, 1)
glat = np.arange(-90, 90.1, 1)
longrid, latgrid = np.meshgrid(glon, glat)
mag0 = igrf12.gridigrf12(t=date, glat=latgrid, glon=longrid, alt_km=0.0)
mag150 = igrf12.gridigrf12(t=date, glat=latgrid, glon=longrid, alt_km=150.0)
# Declination
#ai = plt.contour(longrid, latgrid, mag0.decl.values, levels=np.arange(-30,30.1,1),
# cmap='bwr', transform=ccrs.PlateCarree())
#ai = plt.contour(longrid, latgrid, mag150.decl.values, levels=np.arange(-30,30.1,1),
# cmap='bwr', transform=ccrs.PlateCarree(), linestyles='dashed')
#plt.contour(longrid, latgrid, mag150.decl.values, levels=np.arange(0,1,1),
# colors='green', transform=ccrs.PlateCarree(), linestyles='solid')
#ai.clabel(inline=True, fmt = '%d', fontsize=12, colors='b')
#Inclination
ai = plt.contour(longrid,
latgrid,
mag0.incl.values,