Error in running image_stats_by_zone: "All arrays must be of the same length" #1737

luxizhou · 2023-09-27T04:04:45Z

luxizhou
Sep 27, 2023

Hi,

I was following the example notebook 108 to get the maximum rainfall out of each land-use type. The error message is "ValueError: All arrays must be of the same length". I traced back to the source code and did find the 'keys' and 'values' are of different length, seems to due some landuse type does not get image coverage. But I couldn't figure out a way to get around ...

I paste my script and the full error message extract here. Anyone could have a look and suggest how to fix the error would be very very much appreciated!

Luxi

My sript that results in error###############

import geopandas as gpd
import ee
import geemap
import geemap.colormaps as cm
ee.Initialize()

time1 = '2021-07-01'
time2 = '2022-08-01'
l8 = (ee.ImageCollection('ECMWF/ERA5_LAND/DAILY_AGGR')
.filterDate(time1, time2)
).select('total_precipitation_sum')

image = l8.max()

world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
geometry = world.loc[world['name'] == 'United States of America', 'geometry'].copy().iloc[0]
geometry = ee.Geometry(geometry.geo_interface)
clipped_image = image.clip(geometry)

landcover = ee.Image("USGS/NLCD_RELEASES/2019_REL/NLCD/2019").select('landcover')

original image used in example:

#dem = ee.Image('USGS/3DEP/10m')
#stats = geemap.image_stats_by_zone(dem, landcover, reducer='MAXIMUM')

#not working:
stats1 = geemap.image_stats_by_zone(clipped_image, landcover, reducer='MAXIMUM',scale=20000)

#not working either：
stats1 = geemap.image_stats_by_zone(clipped_image, landcover, region=geometry,reducer='MAXIMUM',scale=20000)

full extract of error message below

ValueError Traceback (most recent call last)
Cell In[32], line 27
21 landcover = ee.Image("USGS/NLCD_RELEASES/2019_REL/NLCD/2019").select('landcover')
23 # original image used in example:
24 #dem = ee.Image('USGS/3DEP/10m')
25 #stats = geemap.image_stats_by_zone(dem, landcover, reducer='MAXIMUM')
---> 27 stats1 = geemap.image_stats_by_zone(clipped_image, landcover,region=geometry, reducer='MAXIMUM',scale=20000)

File ~\AppData\Local\anaconda3\envs\gee\Lib\site-packages\geemap\common.py:7635, in image_stats_by_zone(image, zones, out_csv, labels, region, scale, reducer, bestEffort, **kwargs)
7633 df = pd.DataFrame({"zone": keys, "label": labels, "stat": values})
7634 else:
-> 7635 df = pd.DataFrame({"zone": keys, "stat": values})
7637 if out_csv is not None:
7638 check_file_path(out_csv)

File ~\AppData\Local\anaconda3\envs\gee\Lib\site-packages\pandas\core\frame.py:736, in DataFrame.init(self, data, index, columns, dtype, copy)
730 mgr = self._init_mgr(
731 data, axes={"index": index, "columns": columns}, dtype=dtype, copy=copy
732 )
734 elif isinstance(data, dict):
735 # GH#38939 de facto copy defaults to False only in non-dict cases
--> 736 mgr = dict_to_mgr(data, index, columns, dtype=dtype, copy=copy, typ=manager)
737 elif isinstance(data, ma.MaskedArray):
738 from numpy.ma import mrecords

File ~\AppData\Local\anaconda3\envs\gee\Lib\site-packages\pandas\core\internals\construction.py:503, in dict_to_mgr(data, index, columns, dtype, typ, copy)
499 else:
500 # dtype check to exclude e.g. range objects, scalars
501 arrays = [x.copy() if hasattr(x, "dtype") else x for x in arrays]
--> 503 return arrays_to_mgr(arrays, columns, index, dtype=dtype, typ=typ, consolidate=copy)

File ~\AppData\Local\anaconda3\envs\gee\Lib\site-packages\pandas\core\internals\construction.py:114, in arrays_to_mgr(arrays, columns, index, dtype, verify_integrity, typ, consolidate)
111 if verify_integrity:
112 # figure out the index, if necessary
113 if index is None:
--> 114 index = _extract_index(arrays)
115 else:
116 index = ensure_index(index)

File ~\AppData\Local\anaconda3\envs\gee\Lib\site-packages\pandas\core\internals\construction.py:677, in _extract_index(data)
675 lengths = list(set(raw_lengths))
676 if len(lengths) > 1:
--> 677 raise ValueError("All arrays must be of the same length")
679 if have_dicts:
680 raise ValueError(
681 "Mixing dicts with non-Series may lead to ambiguous ordering."
682 )

ValueError: All arrays must be of the same length