"EEException: Date: Parameter 'value' is required" when trying to download ASTER or SRTM data

[chrislcosgrove]

Thanks for the great tool!

When I try to download an ASTER or SRTM elevation image clipped by an AOI the error "EEException: Date: Parameter 'value' is required" is produced.

Code:
aoi_ASTER = ee.Image('NASA/ASTER_GED/AG100_003').select('elevation').clip(aoi)
aoi_ASTER_ds = aoi_ASTER.wx.to_xarray(scale=50, crs='EPSG:6931')

Error:
`---------------------------------------------------------------------------
HttpError Traceback (most recent call last)
~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/ee/data.py in _execute_cloud_call(call, num_retries)
333 try:
--> 334 return call.execute(num_retries=num_retries)
335 except googleapiclient.errors.HttpError as e:

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/googleapiclient/_helpers.py in positional_wrapper(*args, **kwargs)
133 logger.warning(message)
--> 134 return wrapped(*args, **kwargs)
135

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/googleapiclient/http.py in execute(self, http, num_retries)
914 if resp.status >= 300:
--> 915 raise HttpError(resp, content, uri=self.uri)
916 return self.postproc(resp, content)

HttpError: <HttpError 400 when requesting https://earthengine.googleapis.com/v1alpha/projects/earthengine-legacy/value:compute?prettyPrint=false&alt=json returned "Date: Parameter 'value' is required.". Details: "Date: Parameter 'value' is required.">

During handling of the above exception, another exception occurred:

EEException Traceback (most recent call last)
/var/folders/9t/w440ycrj6z94kk6yxbspq8n40000gn/T/ipykernel_56124/1447908745.py in
1 # Get into xarray datasets
----> 2 overuman_ASTER_ds = overuman_ASTER.wx.to_xarray(scale=50, crs='EPSG:4236')
3 overuman_ASTER_ds

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/wxee/image.py in to_xarray(self, path, region, scale, crs, masked, nodata, progress, max_attempts)
80 """
81 with tempfile.TemporaryDirectory(prefix=constants.TMP_PREFIX) as tmp:
---> 82 files = self.to_tif(
83 out_dir=tmp,
84 region=region,

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/wxee/image.py in to_tif(self, out_dir, description, region, scale, crs, file_per_band, masked, nodata, progress, max_attempts)
161 )
162
--> 163 url = self._get_url(region, scale, crs, file_per_band, nodata, max_attempts)
164
165 tifs = self._url_to_tif(

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/wxee/image.py in _get_url(self, region, scale, crs, file_per_band, nodata, max_attempts)
237 url = img.getDownloadURL(
238 params=dict(
--> 239 name=image_id.getInfo(),
240 scale=scale,
241 crs=crs,

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/ee/computedobject.py in getInfo(self)
96 The object can evaluate to anything.
97 """
---> 98 return data.computeValue(self)
99
100 def encode(self, encoder):

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/ee/data.py in computeValue(obj)
670 The result of evaluating that object on the server.
671 """
--> 672 return _execute_cloud_call(
673 _get_cloud_api_resource().projects().value().compute(
674 body={'expression': serializer.encode(obj, for_cloud_api=True)},

~/opt/miniconda3/envs/SnowSat/lib/python3.9/site-packages/ee/data.py in _execute_cloud_call(call, num_retries)
334 return call.execute(num_retries=num_retries)
335 except googleapiclient.errors.HttpError as e:
--> 336 raise _translate_cloud_exception(e)
337
338

EEException: Date: Parameter 'value' is required.`

[aazuspan]

Hi @chrislcosgrove, that ASTER image is missing a system:time_start property, which is required by to_xarray. As a workaround, you can give it a system:time_start using the set method before you export it, like so:

aoi_ASTER = aoi_ASTER.set("system:time_start", ee.Date("2000"))

That should resolve your problem, but feel free to re-open if it doesn't.