Re: Scale factor and offset problem

Perhaps you should open it twice, once with enhance, the other without?


Didier Earith wrote:
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
==============================================================================


  • 2007 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the netcdf-java archives: