我正在尝试将 Lambert Conformal Conical 卫星图像叠加到 Holoviews 交互式地图上。我可以很好地映射卫星图像,但我不知道如何正确地将这张地图转换到 Holoviews 地图上。下面是我使用 Unidata Siphon 库抓取数据的可重现代码。
导入包
from datetime import datetime
import matplotlib.pyplot as plt
from netCDF4 import Dataset
from siphon.catalog import TDSCatalog
import holoviews as hv
import geoviews as gv
import geoviews.feature as gf
from cartopy import crs
from cartopy import feature as cf
hv.extension('bokeh')
抓取数据并创建图形
date=datetime.utcnow()
idx=-2
regionstr = 'CONUS'
channelnum = 13
datestr = str(date.year) + "%02d"%date.month + "%02d"%date.day
channelstr = 'Channel' + "%02d"%channelnum
cat = TDSCatalog('http://thredds-test.unidata.ucar.edu/thredds/catalog/satellite/goes16/GOES16/' + regionstr +
'/' + channelstr + '/' + datestr + '/catalog.xml')
ds = cat.datasets[idx].remote_access(service='OPENDAP')
x = ds.variables['x'][:]
y = ds.variables['y'][:]
z = ds.variables['Sectorized_CMI'][:]
proj_var = ds.variables[ds.variables['Sectorized_CMI'].grid_mapping]
# Create a Globe specifying a spherical earth with the correct radius
globe = ccrs.Globe(ellipse='sphere', semimajor_axis=proj_var.semi_major,
semiminor_axis=proj_var.semi_minor)
proj = ccrs.LambertConformal(central_longitude=proj_var.longitude_of_central_meridian,
central_latitude=proj_var.latitude_of_projection_origin,
standard_parallels=[proj_var.standard_parallel],
globe=globe)
fig = plt.figure(figsize=(14, 10))
ax = fig.add_subplot(1, 1, 1, projection=proj)
ax.coastlines(resolution='50m', color='lightblue')
ax.add_feature(cf.STATES, linestyle=':', edgecolor='lightblue')
ax.add_feature(cf.BORDERS, linewidth=1, edgecolor='lightblue')
for im in ax.images:
im.remove()
im = ax.imshow(z, extent=(x.min(), x.max(), y.min(), y.max()), origin='upper', cmap='jet')
plt.colorbar(im)
现在使用 Holoviews(使用 Bokeh 后端)绘制交互式图像
goes = hv.Dataset((x, y, z),['Lat', 'Lon'], 'ABI13')
%opts Image (cmap='jet') [width=1000 height=800 xaxis='bottom' yaxis='left' colorbar=True toolbar='above' projection=proj]
goes.to.image()* gf.coastline().options(projection=crs.LambertConformal(central_longitude=proj_var.longitude_of_central_meridian,central_latitude=proj_var.latitude_of_projection_origin,standard_parallels=[proj_var.standard_parallel],globe=globe))
尽管我发现有关兰伯特保形圆锥投影的 Holoviews 文档很少,但我一定不能正确翻译它。我愿意使用任何其他交互式地图包。我的主要愿望是能够相对快速地绘制,正确地在图像上获得州/国家线,并能够放大。我尝试过 folium,但也遇到了投影问题。