Re: Scale factor and offset problem

Hi John


Thanks for you answer.

In some cases, I need  to unpack and repack data, because I need to extract 
data according to user's crtiteria, among others, data value ( ie 
temperature between  10 and 30).

I use NetcdfDataset.acquireDataset() for performance as described in 
documentation.

I also could use NetcdfDataset.openDataset() with "enhance" parameter set 
to false, but  I need to add Coordinate Systems, that's also why I use the 
"enhance" flag to true (acquireDataset() or openDataset()).

Didier



At 18:05 19/06/2007, John Caron wrote:
> Hi Didier:
>
> Is there some reason to unpack and repack?
>
> If you open with NetcdfDataset.openFile() it will not get unpacked - you 
> will have the original variable and data.
>
> John
>
> Didier Earith wrote:
> > Hi all,
> > I have a problem with scale factor and offset when I use th netcdf java 
> > API (v2.2.20).
> > I have to extract netcdf variables with scale_factor and offset 
> > attributes and write the results as another netcdf file.
> > The NetcdfDataset class automatically deals with scale_factor and offset 
> > attributes when it opens dataset, and that's right (but it removed 
> > scale_factor and add_offset attributes)
> > But when I want to write variables into another netcdf file, I need to 
> > have the data type, the scale factor and offset values of the original 
> > variables to packed data again.
> > The VariableDS class provides a public getOriginalDatatype API, that's OK.
> > But scale factor and offset attribute of the VariableDS class are private 
> > and there is no API get them.
> > I saw the getOriginalVariable in the VariableDS class which return the 
> > original variable with the scale_factor and add_offset attributes. But 
> > unfortunately, this API is not visible (private) :
> >  ucar.nc2.Variable getOriginalVariable() {
> >     *return* orgVar; // proxy.getOriginalVariable();
> >   }
> > So, how can I get the scale factor and offset values with netcdf java API 
> > to pack again the variables.
> > Didier.
>
>
>                           Cliquez sur l'url suivante 
> https://www.mailcontrol.com/sr/8!q3CiRmgtQvlGuCKKYE0NjoltADyPBlRy3JPOjpssZhyReyAo6au7C!kks57+B1buxs1PiJPWRh90cAXi4VZoXd5s8WQXStsBQcnHsTGa1AYWNtNXzipbO9vW8zU2JYc6LAtKacDpEhSGvppppmJUynrsDwiiQ09ZQZFPA55AdtsrCGZe+PlFOmZV7AVlr5jYqyKPEgQJ9WlXfwQkELAaC8nK3p6uY3 
>
>                    si ce message est indésirable (pourriel).


===============================================================================
To unsubscribe netcdf-java, visit:
http://www.unidata.ucar.edu/mailing-list-delete-form.html
===============================================================================