I am looking to replace a number with NaN in numpy and am looking for a function like numpy.nan_to_num, except in reverse.
The number is likely to change as different arrays are processed because each can have a uniquely define NoDataValue. I have see people using dictionaries, but the arrays are large and filled with both positive and negative floats. I suspect that it is not efficient to try to load all of these into anything to create keys.
I tried using the following and numpy requiring that I use any() or all(). I realize that I need to iterate element wise, but hope that a built-in function can achieve this.
def replaceNoData(scanBlock, NDV): for n, i in enumerate(array): if i == NDV: scanBlock[n] = numpy.nan
NDV is GDAL's no data value and array is a numpy array.
Is a masked array the way to go perhaps?
nan_to_num() in Python. numpy. nan_to_num() function is used when we want to replace nan(Not A Number) with zero and inf with finite numbers in an array. It returns (positive) infinity with a very large number and negative infinity with a very small (or negative) number.
nan is NOT equal to nan At first, reading that np. nan == np. nan is False can trigger a reaction of confusion and frustration.
In Python, NumPy with the latest version where nan is a value only for floating arrays only which stands for not a number and is a numeric data type which is used to represent an undefined value. In Python, NumPy defines NaN as a constant value.
A[A==NDV]=numpy.nan
A==NDV will produce a boolean array that can be used as an index for A
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