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A Jupyter notebook showing how to use Python to access the NCEI radar archive on Amazon S3 through Unidata's THREDDS server.
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@tjlang
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tjlang commented Oct 28, 2015

I get the following error when trying to execute line 2 (the RadarServer declaration):


KeyError Traceback (most recent call last)
in ()
1 from siphon.radarserver import RadarServer
----> 2 rs = RadarServer('http://thredds-aws.unidata.ucar.edu/thredds/radarServer/nexrad/level2/S3/')

/Users/tjlang/anaconda/lib/python2.7/site-packages/siphon/radarserver.pyc in init(self, url)
66 if url.endswith(xmlfile):
67 url = url[:-len(xmlfile)]
---> 68 super(RadarServer, self).init(url)
69
70 def _get_metadata(self):

/Users/tjlang/anaconda/lib/python2.7/site-packages/siphon/http_util.pyc in init(self, url)
345 self._base = url
346 self._session = create_http_session()
--> 347 self._get_metadata()
348
349 def get_query(self, query):

/Users/tjlang/anaconda/lib/python2.7/site-packages/siphon/radarserver.pyc in _get_metadata(self)
69
70 def _get_metadata(self):
---> 71 ds_cat = TDSCatalog(self.url_path('dataset.xml'))
72 self.metadata = ds_cat.metadata
73 self.variables = set(k.split('/')[0] for k in self.metadata['variables'].keys())

/Users/tjlang/anaconda/lib/python2.7/site-packages/siphon/catalog.pyc in init(self, catalog_url)
55
56 # If we were given an HTML link, warn about it and try to fix to xml
---> 57 if 'html' in resp.headers['content-type']:
58 import warnings
59 new_url = self.catalog_url.replace('html', 'xml')

/Users/tjlang/anaconda/lib/python2.7/site-packages/requests/structures.pyc in getitem(self, key)
52
53 def getitem(self, key):
---> 54 return self._store[key.lower()][1]
55
56 def delitem(self, key):

KeyError: 'content-type'

@dopplershift
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Are you, by chance, coming from a non-edu domain? Since the TDS is locked down to .edu only, siphon will only work there?

I need to catch the error and be more clear about what's going on (obviously), but the root cause is that you're getting a 403 (Unauthorized) error.

@drussellwx
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I am having the same 'content-type' error. I am not on an edu domain. Any way to get around this TDS lock down?

@dopplershift
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Sorry, we kinda have to be careful of data charges. One option, if you're looking for data from the last two weeks is to use our server at http://thredds.ucar.edu/thredds/

The other option is that you can browse and downloda the data over http directly from the S3 bucket at https://noaa-nexrad-level2.s3.amazonaws.com/index.html

@dopplershift
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For anyone else encountering this, we have relocated the server to https://tds-nexrad.scigw.unidata.ucar.edu and it's no longer locked down.

@ebdavison
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ebdavison commented Mar 31, 2022

I am also getting an error trying to run thiswith:
Fedora 35
python 3.10.3
pyproj 3.3.0
cartopy 0.20.1

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
/opt/Data/Personal/NextCloud/Documents/IT/GIS/python_to_access_nexrad.ipynb Cell 25' in <module>
      [1](vscode-notebook-cell:/opt/Data/Personal/NextCloud/Documents/IT/GIS/python_to_access_nexrad.ipynb#ch0000024?line=0)[ import matplotlib.pyplot as plt
----> ]()[2](vscode-notebook-cell:/opt/Data/Personal/NextCloud/Documents/IT/GIS/python_to_access_nexrad.ipynb#ch0000024?line=1)[ import cartopy.crs as ccrs
      ]()[3](vscode-notebook-cell:/opt/Data/Personal/NextCloud/Documents/IT/GIS/python_to_access_nexrad.ipynb#ch0000024?line=2)[ import cartopy.feature as cfeature
      ]()[5](vscode-notebook-cell:/opt/Data/Personal/NextCloud/Documents/IT/GIS/python_to_access_nexrad.ipynb#ch0000024?line=4)[ def new_map(fig, lon, lat):
      ]()[6](vscode-notebook-cell:/opt/Data/Personal/NextCloud/Documents/IT/GIS/python_to_access_nexrad.ipynb#ch0000024?line=5)[     # Create projection centered on the radar. This allows us to use x
      ]()[7](vscode-notebook-cell:/opt/Data/Personal/NextCloud/Documents/IT/GIS/python_to_access_nexrad.ipynb#ch0000024?line=6)[     # and y relative to the radar.

File /usr/lib64/python3.10/site-packages/cartopy/__init__.py:107, in <module>
    ]()[102](file:///usr/lib64/python3.10/site-packages/cartopy/__init__.py?line=101)[     pass
    ]()[105](file:///usr/lib64/python3.10/site-packages/cartopy/__init__.py?line=104)[ # Commonly used sub-modules. Imported here to provide end-user
    ]()[106](file:///usr/lib64/python3.10/site-packages/cartopy/__init__.py?line=105)[ # convenience.
--> ]()[107](file:///usr/lib64/python3.10/site-packages/cartopy/__init__.py?line=106)[ import cartopy.crs
    ]()[108](file:///usr/lib64/python3.10/site-packages/cartopy/__init__.py?line=107)[ import cartopy.feature

File /usr/lib64/python3.10/site-packages/cartopy/crs.py:22, in <module>
     ]()[20](file:///usr/lib64/python3.10/site-packages/cartopy/crs.py?line=19)[ import numpy as np
     ]()[21](file:///usr/lib64/python3.10/site-packages/cartopy/crs.py?line=20)[ import shapely.geometry as sgeom
---> ]()[22](file:///usr/lib64/python3.10/site-packages/cartopy/crs.py?line=21)[ from pyproj import Transformer
     ]()[23](file:///usr/lib64/python3.10/site-packages/cartopy/crs.py?line=22)[ from pyproj.exceptions import ProjError
     ]()[24](file:///usr/lib64/python3.10/site-packages/cartopy/crs.py?line=23)[ from shapely.prepared import prep

File /usr/lib64/python3.10/site-packages/pyproj/__init__.py:57, in <module>
     ]()[50](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=49)[ from pyproj._datadir import (  # noqa: F401 pylint: disable=unused-import
     ]()[51](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=50)[     _pyproj_global_context_initialize,
     ]()[52](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=51)[     set_use_global_context,
     ]()[53](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=52)[ )
     ]()[54](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=53)[ from pyproj._show_versions import (  # noqa: F401 pylint: disable=unused-import
     ]()[55](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=54)[     show_versions,
     ]()[56](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=55)[ )
---> ]()[57](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=56)[ from pyproj.crs import CRS  # noqa: F401 pylint: disable=unused-import
     ]()[58](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=57)[ from pyproj.database import (  # noqa: F401 pylint: disable=unused-import
     ]()[59](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=58)[     get_authorities,
     ]()[60](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=59)[     get_codes,
     ]()[61](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=60)[     get_units_map,
     ]()[62](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=61)[ )
     ]()[63](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=62)[ from pyproj.exceptions import (  # noqa: F401 pylint: disable=unused-import
     ]()[64](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=63)[     DataDirError,
     ]()[65](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=64)[     ProjError,
     ]()[66](file:///usr/lib64/python3.10/site-packages/pyproj/__init__.py?line=65)[ )

File /usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py:16, in <module>
      ]()[1](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=0)[ """
      ]()[2](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=1)[ This module interfaces with PROJ to produce a pythonic interface
      ]()[3](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=2)[ to the coordinate reference system (CRS) information through the CRS
      ]()[4](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=3)[ class.
      ]()[5](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=4)[ """
      ]()[7](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=6)[ from pyproj._crs import (  # noqa: F401  pylint: disable=unused-import
      ]()[8](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=7)[     CoordinateOperation,
      ]()[9](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=8)[     CoordinateSystem,
   (...)
     ]()[14](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=13)[     is_wkt,
     ]()[15](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=14)[ )
---> ]()[16](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=15)[ from pyproj.crs.crs import (  # noqa: F401  pylint: disable=unused-import
     ]()[17](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=16)[     CRS,
     ]()[18](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=17)[     BoundCRS,
     ]()[19](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=18)[     CompoundCRS,
     ]()[20](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=19)[     CustomConstructorCRS,
     ]()[21](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=20)[     DerivedGeographicCRS,
     ]()[22](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=21)[     GeocentricCRS,
     ]()[23](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=22)[     GeographicCRS,
     ]()[24](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=23)[     ProjectedCRS,
     ]()[25](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=24)[     VerticalCRS,
     ]()[26](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=25)[ )
     ]()[27](file:///usr/lib64/python3.10/site-packages/pyproj/crs/__init__.py?line=26)[ from pyproj.exceptions import CRSError

File /usr/lib64/python3.10/site-packages/pyproj/crs/crs.py:27, in <module>
     ]()[11](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=10)[ from typing import Any, Callable, Dict, List, Optional, Tuple, Union
     ]()[13](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=12)[ from pyproj._crs import (
     ]()[14](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=13)[     _CRS,
     ]()[15](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=14)[     AreaOfUse,
   (...)
     ]()[25](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=24)[     is_wkt,
     ]()[26](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=25)[ )
---> ]()[27](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=26)[ from pyproj.crs._cf1x8 import (
     ]()[28](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=27)[     _GEOGRAPHIC_GRID_MAPPING_NAME_MAP,
     ]()[29](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=28)[     _GRID_MAPPING_NAME_MAP,
     ]()[30](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=29)[     _INVERSE_GEOGRAPHIC_GRID_MAPPING_NAME_MAP,
     ]()[31](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=30)[     _INVERSE_GRID_MAPPING_NAME_MAP,
     ]()[32](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=31)[     _horizontal_datum_from_params,
     ]()[33](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=32)[     _try_list_if_string,
     ]()[34](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=33)[ )
     ]()[35](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=34)[ from pyproj.crs.coordinate_operation import ToWGS84Transformation
     ]()[36](file:///usr/lib64/python3.10/site-packages/pyproj/crs/crs.py?line=35)[ from pyproj.crs.coordinate_system import Cartesian2DCS, Ellipsoidal2DCS, VerticalCS

File /usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py:11, in <module>
      ]()[8](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=7)[ import warnings
     ]()[10](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=9)[ from pyproj._crs import Datum, Ellipsoid, PrimeMeridian
---> ]()[11](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=10)[ from pyproj.crs.coordinate_operation import (
     ]()[12](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=11)[     AlbersEqualAreaConversion,
     ]()[13](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=12)[     AzimuthalEquidistantConversion,
     ]()[14](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=13)[     GeostationarySatelliteConversion,
     ]()[15](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=14)[     HotineObliqueMercatorBConversion,
     ]()[16](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=15)[     LambertAzimuthalEqualAreaConversion,
     ]()[17](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=16)[     LambertConformalConic1SPConversion,
     ]()[18](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=17)[     LambertConformalConic2SPConversion,
     ]()[19](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=18)[     LambertCylindricalEqualAreaConversion,
     ]()[20](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=19)[     LambertCylindricalEqualAreaScaleConversion,
     ]()[21](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=20)[     MercatorAConversion,
     ]()[22](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=21)[     MercatorBConversion,
     ]()[23](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=22)[     OrthographicConversion,
     ]()[24](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=23)[     PolarStereographicAConversion,
     ]()[25](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=24)[     PolarStereographicBConversion,
     ]()[26](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=25)[     PoleRotationNetCDFCFConversion,
     ]()[27](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=26)[     SinusoidalConversion,
     ]()[28](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=27)[     StereographicConversion,
     ]()[29](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=28)[     TransverseMercatorConversion,
     ]()[30](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=29)[     VerticalPerspectiveConversion,
     ]()[31](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=30)[ )
     ]()[32](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=31)[ from pyproj.crs.datum import CustomDatum, CustomEllipsoid, CustomPrimeMeridian
     ]()[33](file:///usr/lib64/python3.10/site-packages/pyproj/crs/_cf1x8.py?line=32)[ from pyproj.exceptions import CRSError

File /usr/lib64/python3.10/site-packages/pyproj/crs/coordinate_operation.py:12, in <module>
      ]()[9](file:///usr/lib64/python3.10/site-packages/pyproj/crs/coordinate_operation.py?line=8)[ from typing import Any
     ]()[11](file:///usr/lib64/python3.10/site-packages/pyproj/crs/coordinate_operation.py?line=10)[ from pyproj._crs import CoordinateOperation
---> ]()[12](file:///usr/lib64/python3.10/site-packages/pyproj/crs/coordinate_operation.py?line=11)[ from pyproj._transformer import PROJ_VERSION
     ]()[13](file:///usr/lib64/python3.10/site-packages/pyproj/crs/coordinate_operation.py?line=12)[ from pyproj.exceptions import CRSError
     ]()[16](file:///usr/lib64/python3.10/site-packages/pyproj/crs/coordinate_operation.py?line=15)[ class AlbersEqualAreaConversion(CoordinateOperation):

ImportError: /usr/lib64/python3.10/site-packages/pyproj/_transformer.cpython-310-x86_64-linux-gnu.so: undefined symbol: proj_trans_bounds]()

@dopplershift
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Author

That looks like a conflict between the Fedora packages for pyproj and PROJ. Given that it's an ImportError when running import cartopy.crs as ccrs, it's definitely not a problem with the code on this gist. I'd recommend raising an issue on the Fedora issue tracker.

@ebdavison
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Understood. Thanks.

@btang8
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btang8 commented Apr 1, 2024

Following the example script exactly, I am encountering an error where catalog.datasets returns an empty list for either real-time or archived queries. Perhaps just a temporary hiccup with the radar server or some change with the backend?

@jrudzin
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jrudzin commented Apr 18, 2024

Having the same issue as btang8 - receiving an empty list even though the data is there

@dopplershift
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Author

I've been digging in, but haven't had any luck so far figuring out what's wrong. I'll keep digging, though.

@btang8
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btang8 commented Apr 26, 2024

FYI, Kevin Tyle shared a sample script with me that accesses radar data in a different way, in case others are looking for a workaround: https://www.atmos.albany.edu/facstaff/ktyle/atm350_2023/core/week12/radar_AWS.html

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