[SAC-HELP] SAC/SACA file format verification

[Chad Trabant]

Hi Dan,

Very cool stuff.  The binary file seems to work fine in sac (the  
reference application), the PQL waveform viewer and my sac2mseed  
converter.

The ASCII/ALPHA file has a small problem.  The recognized NULL value  
is "-12345.00", as you can see from the snippet below from  
SeisMacData.SACA the null value seems to have "61" in place of "00"  
which causes minor havoc with the interpretation.

Chad

-- top of SeisMacData.SACA --
        0.020000      -12345.61      -12345.61      -12345.61       
-12345.61
        0.000000       21.34106      -12345.61      -12345.61       
-12345.61
       -12345.61      -12345.61      -12345.61      -12345.61       
-12345.61
       -12345.61      -12345.61      -12345.61      -12345.61       
-12345.61
       -12345.61      -12345.61      -12345.61      -12345.61       
-12345.61
       -12345.61      -12345.61      -12345.61      -12345.61       
-12345.61
       -12345.61      -12345.61      -12345.61      -12345.61       
-12345.61


On Mar 27, 2009, at 6:44 PM, Daniel Griscom wrote:

> Dear Sirs/Madams,
>
> I'm the author of a free IRIS-supported Macintosh program called  
> SeisMac, which uses Mac laptops' built in accelerometers to convert  
> the laptops into (not very accurate) seismographs. You can find more  
> about it at <http://www.suitable.com/tools/seismac.html>.
>
> I'm finishing off an update which will let you export selected data  
> as a binary SAC or ascii SACA file. I think I've got it right  
> (Global Earthquake Explorer successfully reads the SAC files), but  
> I'd love to have further confirmation. Would any of you be able to  
> review example files and tell me if I've made any format errors? Or,  
> point me to other tools which will read/validate SAC/SACA files?
>
>
> I've uploaded the same set of data in three ways:
>
> - Comma-separated values (all three axis): <http://www.suitable.com/temp/SeisMacData.CSV 
> >
>
> - Binary SAC file (Z axis only): <http://www.suitable.com/temp/SeisMacData.SAC 
> >
>
> - Ascii SACA file (Z axis only): <http://www.suitable.com/temp/SeisMacData.SACA 
> >
>
> (If you have a Mac laptop and would like to play with exporting data  
> yourself, the latest binary is at <http://www.suitable.com/temp/SeisMac30b2.zip 
> >)
>
>
> Thanks,
> Dan
>
> -- 
> Daniel T. Griscom             griscom at suitable.com
> Suitable Systems              http://www.suitable.com/
> 1 Centre Street, Suite 204    (781) 665-0053
> Wakefield, MA  01880-2400
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