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JSONDecodeError when trying an operation

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11-25-2025 05:48 AM
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Leandro-Zamudio
by
Frequent Contributor
‎11-25-2025 05:48 AM

Hi.

I'm trying to use ArcGIS API for Python to run a simple query on two layers from the same service.

https://arcgisv11.sea.gob.cl/server/rest/services/WEBServices/ProyectosSEIA/MapServer

LeandroZamudio_0-1764077975939.png

Using this sample code I try to create a dataframe from the layer data and it works the EIA layer (1) but not in DIA layer (2) even if the layers are almost identical

import pandas as pand
from arcgis.gis import GIS
from arcgis.features import GeoAccessor, GeoSeriesAccessor, FeatureLayerCollection

gis = GIS()
fs_url=r"https://arcgisv11.sea.gob.cl/server/rest/services/WEBServices/ProyectosSEIA/MapServer"
coleccioncapas = FeatureLayerCollection(fs_url)
Capas=coleccioncapas.layers
#for capa in Capas:
#    print(capa.properties.name)
capa_data=Capas[1]
df_data = pand.DataFrame.spatial.from_layer(capa_data)
print(df_data.head(5))

 

That's the error.

C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\urllib3\connectionpool.py:1097: InsecureRequestWarning: Unverified HTTPS request is being made to host 'arcgisv11.sea.gob.cl'. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#tls-warnings
  warnings.warn(
C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\urllib3\connectionpool.py:1097: InsecureRequestWarning: Unverified HTTPS request is being made to host 'arcgisv11.sea.gob.cl'. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#tls-warnings
  warnings.warn(
Traceback (most recent call last):
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\requests\models.py", line 974, in json
    return complexjson.loads(self.text, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\json\__init__.py", line 346, in loads
    return _default_decoder.decode(s)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\json\decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\json\decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\features\geo\_accessor.py", line 2683, in from_layer
    return from_layer(layer=layer)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\features\geo\_io\serviceops.py", line 186, in from_layer
    sdf = layer.query(where=query, as_df=True)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\features\layer.py", line 2257, in query
    ).execute()
      ^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\_impl\common\_query.py", line 658, in execute
    return self._query(raw)
           ^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\_impl\common\_query.py", line 679, in _query
    return self._handle_query_exception(query_exception)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\_impl\common\_query.py", line 843, in _handle_query_exception
    raise query_exception
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\_impl\common\_query.py", line 677, in _query
    return self._process_query_result(result, raw)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\_impl\common\_query.py", line 711, in _process_query_result
    features = self._fetch_all_features_by_chunk()
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\_impl\common\_query.py", line 829, in _fetch_all_features_by_chunk
    result = future.result().json()
             ^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\requests\models.py", line 978, in json
    raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "d:\Code\core-python-jupiter\pruebas\testing.py", line 12, in <module>
    df_data = pand.DataFrame.spatial.from_layer(capa_data)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\features\geo\_accessor.py", line 2687, in from_layer
    raise Exception(
Exception: Malformed response from server, could not load the dataset: Expecting value: line 1 column 1 (char 0)

 

 

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1 Reply
AustinAverill
by
Frequent Contributor
16 hours ago

I have found that the pd.DataFrame.spatial.from_layer() method is wildly inconsistent and often has little-to-no helpful traceback for debugging when it randomly decides to work.

 

I would recommend using the query method on the layers instead. You can include the "as_df=True" argument or call the ".sdf" attribute of the queried featureset after the fact. When I tested just now, this method worked fine.

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