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52 netcdf

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Visualizing NetCDF data

Uncomment the following line to install leafmap if needed.

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# !pip install leafmap

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# !pip install xarray rioxarray netcdf4 localtileserver

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from leafmap import leafmap

Download a sample NetCDF dataset.

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url = "https://github.com/opengeos/datasets/releases/download/raster/wind_global.nc"
filename = "wind_global.nc"

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leafmap.download_file(url, output=filename, overwrite=True)

Read the NetCDF dataset.

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data = leafmap.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"
leafmap.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/opengeos/leafmap/raw/master/examples/data/countries.geojson"
)

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m = leafmap.Map(layers_control=True)
m.add_raster(tif, indexes=[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 = leafmap.Map(layers_control=True)
m.add_netcdf(
    filename,
    variables=["v_wind"],
    palette="coolwarm",
    shift_lon=True,
    layer_name="v_wind",
    indexes=[1],
)
m.add_geojson(geojson, layer_name="Countries")
m

Visualizing wind velocity.

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m = leafmap.Map(layers_control=True)
m.add_basemap("CartoDB.DarkMatter")
m.add_velocity(
    filename,
    zonal_speed="u_wind",
    meridional_speed="v_wind",
    color_scale=[
        "rgb(0,0,150)",
        "rgb(0,150,0)",
        "rgb(255,255,0)",
        "rgb(255,165,0)",
        "rgb(150,0,0)",
    ],
)
m