replace -28672 with NaN

I have MODIS image, fill value is -28672(No data area). I want to replace those as NaN. why I am doing this is, I dont want to use those values to further calculations. I used this I(I==-28672)=NaN; but it not displayed as NaN. it displayed as 0. I dont know why it is not working.my image(I) is in type int16.

[mahesh chathuranga]

oh! thankx

Answer 1

[Robert Cumming]

You have answered your own question - your data type is a int16. A NaN is a double

See:

class(NaN)

It is type double.