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NCDF_ATTCOPY and typecasting [message #49798] Fri, 18 August 2006 10:26 Go to next message
alexzcervantes@gmail. is currently offline  alexzcervantes@gmail.
Messages: 7
Registered: July 2006
Junior Member
Hello All,

I am newb to NetCDF and IDL so bear with me :)

Here's my situation:

I am reading in a data array of type FLOAT, and creating a new NetCDF
file and writing the data array to the new file in type BYTE. I can do
this fine. However, when I try to do a ncdf_attcopy on the variable
attributes from the float array to my new byte array, it fails. I do
know that when doing a varput, the datatype of the array and its
attributes need to be the same.

Does anyone know any way around this where I can maybe do a typecast
from float to byte using ncdf_attcopy?

Thanks in advance,
Alex

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Re: NCDF_ATTCOPY and typecasting [message #49864 is a reply to message #49798] Mon, 21 August 2006 10:08 Go to previous messageGo to next message
K. Bowman is currently offline  K. Bowman
Messages: 330
Registered: May 2000
Senior Member
In article <1156178416.968784.228920@74g2000cwt.googlegroups.com>,
"alexzcervantes@gmail.com" <alexzcervantes@gmail.com> wrote:

> Doh! I guess a better question would be, when using ncdf_attget, is
> there a way to determine tye type of the attribute you are reading? I
> am thinking I need special 'if' statement to check if the attribute is
> of type string, then write it out as string if it is so.

That would be NCDF_ATTINQ.

Cheers, Ken Bowman

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Re: NCDF_ATTCOPY and typecasting [message #49865 is a reply to message #49798] Mon, 21 August 2006 10:30 Go to previous message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
alexzcervantes@gmail.com writes:

> Okay, after doing more researching, I read that ncdump translates byte
> data into readable string whenever it can. How come it won't do it in
> my case?

Don't know. Maybe this is one of the scenarios in which it can't. :-)

I wouldn't worry too much about it. It is quite common to store
strings as byte arrays. Presumably the user can figure out he
needs a string and cast the byte array to that.

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. (Opata Indian saying, meaning "Perhaps thou
speakest truth.")

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Re: NCDF_ATTCOPY and typecasting [message #49866 is a reply to message #49798] Mon, 21 August 2006 10:11 Go to previous message
alexzcervantes@gmail. is currently offline  alexzcervantes@gmail.
Messages: 7
Registered: July 2006
Junior Member
Okay, after doing more researching, I read that ncdump translates byte
data into readable string whenever it can. How come it won't do it in
my case?

I keep getting:

solar_irradiance:long_name = 115b, 111b, 108b, 97b, 114b, 32b, 105b,
114b, 114b, 97b, 100b, 105b, 97b, 110b, 99b, 101b ;

-Alex
David Fanning wrote:
> alexzcervantes@gmail.com writes:
>
>> Here is a chunk of my code:
>>
>> if(natts gt 0) then begin
>> FOR index = 0L, natts - 1L DO BEGIN
>> ;----Load the attribute name in attribute name array
>> maf_attname = ncdf_attname(mafncid, mafvarid, index)
>> ncdf_attget, mafncid, mafvarid, maf_attname, attval
>> ncdf_attput, cdfid, l2pvarid, maf_attname, attval, /byte
>> ENDFOR
>> endif
>>
>> Everything seems to work except when I have to copy over strings. When
>> I typecast a string to byte, I get output like this:
>>
>> solar_irradiance:_FillValue = -1b ;
>> solar_irradiance:scale_factor = 1b ;
>> solar_irradiance:add_offset = 0b ;
>> solar_irradiance:valid_min = 0b ;
>> solar_irradiance:valid_max = 0b ;
>> solar_irradiance:long_name = 115b, 111b, 108b, 97b, 114b, 32b, 105b,
>> 114b, 114b, 97b, 100b, 105b, 97b, 110b, 99b, 101b ;
>
> So, what do you think is wrong?
>
> IDL> long_name = [115b, 111b, 108b, 97b, 114b, 32b, 105b, 114b, $
> 114b, 97b, 100b, 105b, 97b, 110b, 99b, 101b]
> IDL> print, string(long_name)
> solar irradiance
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming: http://www.dfanning.com/
> Sepore ma de ni thui. (Opata Indian saying, meaning "Perhaps thou
> speakest truth.")

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Re: NCDF_ATTCOPY and typecasting [message #49867 is a reply to message #49798] Mon, 21 August 2006 09:40 Go to previous message
alexzcervantes@gmail. is currently offline  alexzcervantes@gmail.
Messages: 7
Registered: July 2006
Junior Member
Doh! I guess a better question would be, when using ncdf_attget, is
there a way to determine tye type of the attribute you are reading? I
am thinking I need special 'if' statement to check if the attribute is
of type string, then write it out as string if it is so.

-Alex
David Fanning wrote:
> alexzcervantes@gmail.com writes:
>
>> Here is a chunk of my code:
>>
>> if(natts gt 0) then begin
>> FOR index = 0L, natts - 1L DO BEGIN
>> ;----Load the attribute name in attribute name array
>> maf_attname = ncdf_attname(mafncid, mafvarid, index)
>> ncdf_attget, mafncid, mafvarid, maf_attname, attval
>> ncdf_attput, cdfid, l2pvarid, maf_attname, attval, /byte
>> ENDFOR
>> endif
>>
>> Everything seems to work except when I have to copy over strings. When
>> I typecast a string to byte, I get output like this:
>>
>> solar_irradiance:_FillValue = -1b ;
>> solar_irradiance:scale_factor = 1b ;
>> solar_irradiance:add_offset = 0b ;
>> solar_irradiance:valid_min = 0b ;
>> solar_irradiance:valid_max = 0b ;
>> solar_irradiance:long_name = 115b, 111b, 108b, 97b, 114b, 32b, 105b,
>> 114b, 114b, 97b, 100b, 105b, 97b, 110b, 99b, 101b ;
>
> So, what do you think is wrong?
>
> IDL> long_name = [115b, 111b, 108b, 97b, 114b, 32b, 105b, 114b, $
> 114b, 97b, 100b, 105b, 97b, 110b, 99b, 101b]
> IDL> print, string(long_name)
> solar irradiance
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming: http://www.dfanning.com/
> Sepore ma de ni thui. (Opata Indian saying, meaning "Perhaps thou
> speakest truth.")

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Re: NCDF_ATTCOPY and typecasting [message #49887 is a reply to message #49798] Fri, 18 August 2006 13:34 Go to previous message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
alexzcervantes@gmail.com writes:

> Here is a chunk of my code:
>
> if(natts gt 0) then begin
> FOR index = 0L, natts - 1L DO BEGIN
> ;----Load the attribute name in attribute name array
> maf_attname = ncdf_attname(mafncid, mafvarid, index)
> ncdf_attget, mafncid, mafvarid, maf_attname, attval
> ncdf_attput, cdfid, l2pvarid, maf_attname, attval, /byte
> ENDFOR
> endif
>
> Everything seems to work except when I have to copy over strings. When
> I typecast a string to byte, I get output like this:
>
> solar_irradiance:_FillValue = -1b ;
> solar_irradiance:scale_factor = 1b ;
> solar_irradiance:add_offset = 0b ;
> solar_irradiance:valid_min = 0b ;
> solar_irradiance:valid_max = 0b ;
> solar_irradiance:long_name = 115b, 111b, 108b, 97b, 114b, 32b, 105b,
> 114b, 114b, 97b, 100b, 105b, 97b, 110b, 99b, 101b ;

So, what do you think is wrong?

IDL> long_name = [115b, 111b, 108b, 97b, 114b, 32b, 105b, 114b, $
114b, 97b, 100b, 105b, 97b, 110b, 99b, 101b]
IDL> print, string(long_name)
solar irradiance

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. (Opata Indian saying, meaning "Perhaps thou
speakest truth.")

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