[SAC-HELP] Fw:Fwd: how to rotate R T comp into N E ?

[Renate Hartog]

Hello,

Below is a simple example to show how to use rotate to go from any 
orientation to another (orthogonal orientation). "rotate to number" 
changes the azimuth of the first listed component to "number" degrees 
clockwise from N. The second component will be number+90 from N.

You can check the orientation of your two files by listing the value of 
the cmpaz header value (clockwise from N).

-Renate

SAC> r
06100802482.D04A.BHE 06100802482.D04A.BHN
SAC> lh cmpaz


   FILE: 06100802482.D04A.BHE - 1
  --------------------------

      cmpaz = 9.000000e+01

   FILE: 06100802482.D04A.BHN - 2
  --------------------------

      cmpaz = 0.000000e+00
SAC> rotate to gcp
SAC> lh


   FILE: 06100802482.D04A.BHE - 1
  --------------------------

      cmpaz = 2.871565e+02

   FILE: 06100802482.D04A.BHN - 2
  --------------------------

      cmpaz = 1.715649e+01
SAC> rotate to 0.
SAC> lh


   FILE: 06100802482.D04A.BHE - 1
  --------------------------

      cmpaz = 0.000000e+00

   FILE: 06100802482.D04A.BHN - 2
  --------------------------

      cmpaz = 9.000000e+01
SAC>



On Tue, 30 Jun 2009, bjlemon wrote:

> Hi all,
> Thank you for your letter.
> In your letter, you have written how to rotate the N E comp to R T. But my problem is how to rotate the R T comp to N E. I did see the help of sac command "rotate", but there is no instruction abut it? So I wrote a letter again.
>
>
> Best wishes,
>
> Ning Liu and Weitao Wang
>
>
>
>
>
>
>
>
> ---------- Forwarded message ----------
> From: Arthur Snoke<snoke at vt.edu>
> Date: 2009/6/29
> Subject: Re: [SAC-HELP] how to rotate R T comp into N E ?
> To: weitao wang <wangwtustc at gmail.com>
> Cc: sac-help at iris.washington.edu
>
>
> In the help command for rotate, there are options for rotating "to" and "through" a fixed angle.  It would be easy to write a macro that could give you back the N and E components.  I would do test cases to make sure it works correctly for you.
>
> Here is a macro I use to do the "normal" rotation:
>
> r $1$.n $1$.e
> rtr
> rotate to gcp
> write $1$.r $1$.t
> r $1$.r
> chnhdr kcmpnm "radial"
> write over
> r $1$.t
> chnhdr kcmpnm "trnsvers"
> write over
>
> If it is named rotaate.m, one calls it for  abc.n and abc.e using
>
> SAC> m rotate.m abc
>
>
> On Mon, 29 Jun 2009, weitao wang wrote:
>
> Hi,All
> I have a question while rotating horizontal component with sac. We can use "rotate to GCP" to rotate N E into  R T comp,but how to rotate back into N E components? Is there an easy way to do this?
>
>
>
>
>
>
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>
>
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