zonal stats: speed up dask case #572
Merged
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This PR uses the same approach as #568 to improve performance for zonal stats when input data arrays are dask-backed. It computes stats chunk by chunk and then summarizes all the results and return output as a dask DataFrame.
This also limits stats that supported in dask case to a subset of default stats, which is safer since a custom statistics would not be always element-wise thus can produce unexpected results.
nodata_zones
is removed as we already supportzone_ids
, and exclude invalid values (nan, inf) from our calculations.