[Paraview] [EXTERNAL] Paraview can't show grads origin data

[wang]

Dear Kenneth,

Thanks a lot for you effort to reply my mail.

The problem is solve now. It was simpler than it looks. It only because
the data produced in this way is 4-D (x,y,z,t). When I convert it into 
3-D(x,y,t)
everything is fine.

But I have some other problems: the Paraview *crashes* when I'm making 
movie
or just make many png files series. I was forced to cut the time steps 
into many
small pieces in order to keep Paraview running. It makes no difference 
whether
use 1fps or 2**n fps.

A few months ago I could make avi formatted movie without any problem. And
in the time nothing has  changed with my computer. By the way I'm using 
version 3.10.

Cheers!
Xueli


Moreland, Kenneth wrote:
> OK.  I see now.  Clearly I'm not familiar with the GrADS software or its
> data formats.  If someone else on the ParaView mailing list is familiar
> with GrADS it would be great if they speak up, but according to the mail
> archives GrADS has not yet been discussed.
>
>
> I suspect the problem is that ParaView simply does not know how to read
> the type of netCDF files written by GrADS.  NetCDF is not a completely
> specified file format.  Rather, it is a collection of arrays that are
> "self describing."  That is, the arrays and dimensions are named and can
> have properties, but to read them properly you really have to understand
> what these metadata mean.
>
> There are actually several readers in ParaView that use netCDF as the
> underlying technology, but only one that makes an attempt to generally
> read unknown "conventions."  It will assume that arrays are regular grids
> with up to three physical dimensions (x/y/z or lat/lon/z) and optionally a
> time dimension.  Based on about 5 minutes looking at the GrADS web pages,
> I'm guessing that the netCDF file GrADS is outputting contains 5
> dimensional arrays.  In this case, the ParaView reader won't know what to
> do with 5 dimensions and will therefore issue an error if you try to read
> one.  (You never actually said what went wrong, but perhaps that is it.)
>
> I'm sorry that probably none of this is helping.  Ultimately, it sounds
> like a new reader would have to be created for ParaView.
>
> -Ken
>
> On 3/13/12 2:28 AM, "wang"<wang at knmi.nl>  wrote:
>
>    
>> Thanks for your reply.
>>
>> Grads is a software package that widely used by meteorological societies
>>   worldwide. http://www.iges.org/grads/.
>> The nc file I get can  be shown by ferret (which is also a software
>> package
>> used by earth science communities) and Grads (Grads can read binary and
>> data).
>>
>> The problem may occurred by conversion...
>>
>> Xueli
>>
>> Moreland, Kenneth wrote:
>>      
>>> I don't know what you mean by a "grad" or what problem it is causing, so
>>> I'm going to make a total guess.  I am guessing that you mean gradian (a
>>> unit equal to 9/10 of a degree).  Furthermore, because I can't think of
>>> any other way such units would mess you up, I am guessing that you are
>>> trying to write spherical coordinates in terms of gradians, but ParaView
>>> is interpreting them either as degrees or as Cartesian coordinates.
>>>
>>>
>>> Assuming that this is the problem, it is caused by the fact that the
>>> default netCDF reader for ParaView honors the CF convention
>>> (http://cf-pcmdi.llnl.gov), and the CF convention specifies spherical
>>> coordinates in terms of degrees.  To specify angles in any other units
>>> is
>>> to break the convention.
>>>
>>> Your best solution is to convert your gradians to degrees (it's OK to
>>> have
>>> floating-point degrees) and write a netCDF file that properly follows
>>> the
>>> CF convention.
>>>
>>> If I have completely missed the point of your question, you'll have to
>>> better explain what are grads and what problem you are having with them.
>>>
>>> -Ken
>>>
>>> On 3/12/12 10:13 AM, "wang"<wang at knmi.nl>   wrote:
>>>
>>>
>>>        
>>>> Dear Paraview users,
>>>>
>>>> I have problem with data that origin of grads. We have a program to
>>>> convert grads data into NetCDF format. But this data can not be shown
>>>> in
>>>> Paraview. I don't have any problem to show normal nc data.
>>>>
>>>> Have you ever experience the same problem?
>>>>
>>>> Thanks!
>>>> Xueli
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>>>>          
>>>
>>>        
>>
>>      
>
>