[Gdal-dev] modis sinusoidal tiles: bug in gdal?

Christopher Barker Chris.Barker at noaa.gov
Tue Nov 6 12:26:38 EST 2007

Vincent Schut wrote:
> - md says CHARACTERISTICBINSIZE=463.312716527778
> - (6371007.181 * 2pi) / 86400 = 463.31271656938469
> Now which one is non-accurate, their spheroid or their pixel size?

These are the same to single precision floating point -- was all 
storage/calculation done in doubles? I expect not. We all know that 
checking equality is problematic with floating point -- all you can do 
is check that they are the same to the precision expected, and this sure 
looks close to me.

looking closer, they are the same for the first 10 decimal digits, and 
your calculation is based on ten digits input.


Christopher Barker, Ph.D.

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