Hi Daniele:
GRIB projection info is stored in the GRIB file in (at most) 3 bytes, so
has a maximum precision of 24 bits.
Im surprised that you are seeing a problem, it seems unlikely that a
roundoff in the low order bit of a float should matter.
But theres not really a good reason that we couldnt use doubles if needed.
John
On Mon, Apr 20, 2015 at 3:45 AM, Daniele Romagnoli <
daniele.romagnoli@xxxxxxxxxxxxxxxx> wrote:
> Hi List,
> I'm using NetCDF Java 4.5.5.
> I have noticed that when computing the LambertConformal projection
> components (such as latin1, latin2...) in Grib1Gds I'm getting:
>
> latin1 = 25.00001
> latin2 = 25.05002
> dx1 = 13.545001
> dy1 = 13.545001
>
> Instead of:
> latin1 = 25
> latin2 = 25.05
> dx1 = 13.545
> dy1 = 13.545
>
> Plus, I'm getting some additional precision loss when extracting these
> attributes
> from the associated grid_mapping variable, as numbers (double values).
> I will surely investigate more on the topic to become more confident with
> that code and I will read again about representation errors on floating
> point arithmetics so my question could sounds trivial: Why these variables
> and scale constants are floats instead of doubles? (is it for size and
> performance issues?)
>
> Regards,
> Daniele
>
>
>
>
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