Eorr returned when calling extract_pixel_values

[Jack-ee]

Dear Dr. Wu,

I got some error when calling the extract_pixel_values. Is it a bug in my use or a bug in the package?

lat = 19.526390
lon = 109.468799

years = 2018
yeare = 2021
bound = ee.Geometry.Point(lon,lat)

def getNDVI(image):
    return image.normalizedDifference(['sur_refl_b02','sur_refl_b01']).toFloat().rename('NDVI').copyProperties(image)
 
mod09q1 = ee.ImageCollection("MODIS/006/MOD09Q1").filterBounds(bound).filterDate(str(years)+'-01-01',str(yeare)+'-12-31')
imgs = mod09q1.map(getNDVI)
img_ndvi = imgs.select('NDVI').toBands()
pts = geemap.extract_pixel_values(ee_object=img_ndvi,region=bound,scale=250,getInfo=True)
pts

Here is the error message

HttpError Traceback (most recent call last)
~\Anaconda3\envs\pheno\lib\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:

~\Anaconda3\envs\pheno\lib\site-packages\googleapiclient_helpers.py in positional_wrapper(*args, **kwargs)
133 logger.warning(message)
--> 134 return wrapped(*args, **kwargs)
135

~\Anaconda3\envs\pheno\lib\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 "Element.toDictionary: Parameter 'element' is required.". Details: "Element.toDictionary: Parameter 'element' is required.">

During handling of the above exception, another exception occurred:

EEException Traceback (most recent call last)
C:\Users\JACK_D~1\AppData\Local\Temp/ipykernel_21100/4136141119.py in
12 imgs = mod09q1.map(getNDVI)
13 img_ndvi = imgs.select('NDVI').toBands()
---> 14 pts = geemap.extract_pixel_values(ee_object=img_ndvi,region=bound,scale=250,getInfo=True)
15 pts

~\Anaconda3\envs\pheno\lib\site-packages\geemap\common.py in extract_pixel_values(ee_object, region, scale, projection, tileScale, getInfo)
7502 if getInfo:
7503 band_names = ee_object.bandNames().getInfo()
-> 7504 values_tmp = dict_values.getInfo()
7505 values = [values_tmp[i] for i in band_names]
7506 return dict(zip(band_names, values))

~\Anaconda3\envs\pheno\lib\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):

~\Anaconda3\envs\pheno\lib\site-packages\ee\data.py in computeValue(obj)
674 body={'expression': serializer.encode(obj, for_cloud_api=True)},
675 project=_get_projects_path(),
--> 676 prettyPrint=False))['result']
677
678

~\Anaconda3\envs\pheno\lib\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: Element.toDictionary: Parameter 'element' is required.

[giswqs]

It is because the image has nodata. You need to use the .unmask() to set the nodata to zero or other values.

[Jack-ee]

It's great