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How to replace/exlude certain values from data array/plot

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Lukas
Lukas 2014-5-26
评论： MiguelMauricio 2014-5-26
Hey Folks,
I have the following problem: I have SAR-scenes with readings in dB. In some cases the scenes have an edge with values of -1.0E-30. When I plot the data I get a series of data points around 0, which distort the result (see attached picture). I tried to replace these values with the following code:
if true
% SAR_20070116(SAR_20070116 == -1.0e-30)=nan;
end
Unfortunately, the values were not overwritten. Does anyone know how to solve this problem?
  1 个评论
MiguelMauricio
MiguelMauricio 2014-5-26
Let's say you want to remove the data lower than 1e-30. What about?
newArray=oldArray(oldArray>1e-30)
and your horizontal value array becomes
xNew=xOld(oldArray>1e-30)

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回答（1 个）

Roger Wohlwend
Roger Wohlwend 2014-5-26
The problem is that the values are probably not exactly 1.0E-30 but something like 0.9876E-30 or 1.0003E-30. That is why your code does not work. Try the following:
SAR(abs(SAR) < 1E-20) = NaN;
The threshold 1E-20 is chosen arbitrarily. You can choose a different value, if you like.

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