105 netcdf

Visualizing NetCDF data

Uncomment the following line to install geemap if needed.

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# !pip install geemap xarray rioxarray netcdf4 localtileserver

# !pip install geemap xarray rioxarray netcdf4 localtileserver

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import geemap

import geemap

Download a sample NetCDF dataset.

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url = 'https://github.com/giswqs/leafmap/raw/master/examples/data/wind_global.nc'
filename = 'wind_global.nc'

url = 'https://github.com/giswqs/leafmap/raw/master/examples/data/wind_global.nc' filename = 'wind_global.nc'

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geemap.download_file(url, output=filename)

geemap.download_file(url, output=filename)

Read the NetCDF dataset.

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data = geemap.read_netcdf(filename)
data

data = geemap.read_netcdf(filename) data

Convert the NetCDF dataset to GeoTIFF. Note that the longitude range of the NetCDF dataset is [0, 360]. We need to convert it to [-180, 180] by setting shift_lon=True so that it can be displayed on the map.

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tif = 'wind_global.tif'
geemap.netcdf_to_tif(filename, tif, variables=['u_wind', 'v_wind'], shift_lon=True)

tif = 'wind_global.tif' geemap.netcdf_to_tif(filename, tif, variables=['u_wind', 'v_wind'], shift_lon=True)

Add the GeoTIFF to the map. We can also overlay the country boundary on the map.

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geojson = 'https://github.com/giswqs/leafmap/raw/master/examples/data/countries.geojson'

geojson = 'https://github.com/giswqs/leafmap/raw/master/examples/data/countries.geojson'

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m = geemap.Map(layer_ctrl=True)
m.add_raster(tif, band=[1], palette='coolwarm', layer_name='u_wind')
m.add_geojson(geojson, layer_name='Countries')
m

m = geemap.Map(layer_ctrl=True) m.add_raster(tif, band=[1], palette='coolwarm', layer_name='u_wind') m.add_geojson(geojson, layer_name='Countries') m

You can also use the add_netcdf() function to add the NetCDF dataset to the map without having to convert it to GeoTIFF explicitly.

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m = geemap.Map(layer_ctrl=True)
m.add_netcdf(
    filename,
    variables=['v_wind'],
    palette='coolwarm',
    shift_lon=True,
    layer_name='v_wind',
)
m.add_geojson(geojson, layer_name='Countries')
m

m = geemap.Map(layer_ctrl=True) m.add_netcdf( filename, variables=['v_wind'], palette='coolwarm', shift_lon=True, layer_name='v_wind', ) m.add_geojson(geojson, layer_name='Countries') m

Visualizing wind velocity.

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m = geemap.Map(layer_ctrl=True)
m.add_basemap('CartoDB.DarkMatter')
m.add_velocity(filename, zonal_speed='u_wind', meridional_speed='v_wind')
m

m = geemap.Map(layer_ctrl=True) m.add_basemap('CartoDB.DarkMatter') m.add_velocity(filename, zonal_speed='u_wind', meridional_speed='v_wind') m